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Because of their robustness and orthogonal reactivity features, alkyl germanes bear significant potential as functional handles for the construction of C(sp 3 )-rich scaffolds, especially in the context of modular synthetic approaches. However, to date, only radical-based reactivity has been accessible from these functional handles, which limits the types of possible decorations. Here, we describe the first general C(sp 3 )-heteroatom bond formation of alkyl germanes (-GeEt 3 ) by leveraging electrochemistry to unlock polar reactivity. This approach allowed us to couple C(sp 3 )-GeEt 3 with a variety of nucleophiles to construct ethers, esters, amines, amides, sulfonamides, sulfides, as well as C-P, C-F, and C-C bonds. The compatibility of the electrochemical approach with a modular synthetic strategy of a C 1 motif was also showcased, involving the sequential functionalization of Cl, Bpin, and ultimately GeEt 3 via electrochemistry.

The ever increasing demands for greater sustainability and lower energy usage in chemical processes call for fundamentally new approaches and reactivity principles. In this context, the pronounced prevalence of odd-oxidation states in less precious metals bears untapped potential for fundamentally distinct reactivity modes via metalloradical catalysis 1-3 . Contrary to the well-established reactivity paradigm that organic free radicals, upon addition to a vinylcyclopropane, lead to rapid ring opening under strain release-a transformation that serves widely as a mechanistic probe (radical clock) 4 for the intermediacy of radicals 5 -we herein show that a metal-based radical, that is, a Ni (I) metalloradical, triggers reversible cis/trans isomerization instead of opening. The isomerization proceeds under chiral inversion and, depending on the substitution pattern, occurs at room temperature in less than 5 min, requiring solely the addition of the non-precious catalyst. Our combined computational and experimental mechanistic studies support metalloradical catalysis as origin of this profound reactivity, rationalize the observed stereoinversion and reveal key reactivity features of the process, including its reversibility. These insights enabled the iterative thermodynamic enrichment of enantiopure cis/trans mixtures towards a single diastereomer through multiple Ni (I) catalysis rounds and also extensions to divinylcyclopropanes, which constitute strategic motifs in natural product- and total syntheses 6 . While the trans-isomer usually requires heating at approximately 200 °C to trigger thermal isomerization under racemization to cis-divinylcyclopropane, which then undergoes facile Cope-type rearrangement, the analogous contra-thermodynamic process is herein shown to proceed under Ni (I) metalloradical catalysis under mild conditions without any loss of stereochemical integrity, enabling a mild and stereochemically pure access to seven-membered rings, fused ring systems and spirocycles., (© 2024. The Author(s).)

We report the triply selective and sequential diversification of a single C sp 3 carbon carrying Cl, Bpin and GeEt 3 for the modular and programmable construction of sp 3 -rich molecules. Various functionalizations of C sp 3 -Cl and C sp 3 -BPin (e.g. alkylation, arylation, homologation, amination, hydroxylation) were tolerated by the C sp 3 -GeEt 3 group. Moreover, the methodological repertoire of alkyl germane functionalization was significantly expanded beyond the hitherto known Giese addition and arylation to alkynylation, alkenylation, cyanation, halogenation, azidation, C-S bond formation as well as the first demonstration of stereo-selective functionalization of a C sp 3 -[Ge] bond., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Within the sphere of traditional Pd 0 /Pd II cross coupling reactions, organogermanes have been historically outperformed both in terms of scope and reactivity by more conventional transmetalating reagents. Subsequently, this class of compounds has been largely underutilized as a coupling partner in bond-forming strategies. Most recent studies, however, have shown that alternative modes of activation of these notoriously robust building blocks transform organogermanes into the most reactive site of the molecule-capable of outcompeting other functional groups (such as boronic acids, esters and silanes) for both C-C and C-heteroatom bond formation. As a result, over the past few years, the literature has increasingly featured methodologies that explore the potential of organogermanes as chemoselective and orthogonal coupling partners. Herein we highlight some of these recent advances in the field of organogermane chemistry both with respect to their synthesis and applications in synthetic and catalytic transformations., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The first efficient access to N -difluoromethyl amides, carbamates, thiocarbamates, ureas, formamides, and their derivatives is reported herein. The synthetic strategy relies on the initial synthesis and straightforward derivatization of N -CF 2 H carbamoyl fluorides, which were prepared through a desulfurization-fluorination of thioformamides (─NH─C(H)═S) coupled with carbonylation. The newly made N -CF 2 H carbonyl compounds proved to be highly robust and compatible with numerous chemical transformations and downstream derivatizations, underscoring the potential of this novel motif as a building block in complex functional molecules.

The observation of post-transition-state dynamic effects in the context of metal-based transformation is rare. To date, there has been no reported case of a dynamic effect for the widely employed class of palladium-mediated coupling reactions. We performed an experimental and computational study of the trifluoromethylation of Pd (II) F, which is a key step in the Pd (0) /Pd (II) -catalyzed trifluoromethylation of aryl halides or acid fluorides. Our experiments show that the cis / trans speciation of the formed Pd (II) CF 3 is highly solvent- and transmetalation reagent-dependent. We employed GFN2-xTB- and B3LYP-D3-based molecular dynamics trajectory calculations (with and without explicit solvation) along with high-level QM calculations and found that depending on the medium, different transmetalation mechanisms appear to be operative. A statistically representative number of Born-Oppenheimer molecular dynamics (MD) simulations suggest that in benzene, a difluorocarbene is generated in the transmetalation with R 3 SiCF 3 , which subsequently recombines with the Pd via two distinct pathways, leading to either the cis - or trans- Pd (II) CF 3 . Conversely, GFN2-xTB simulations in MeCN suggest that in polar/coordinating solvents an ion-pair mechanism is dominant. A CF 3 anion is initially liberated and then rebinds with the Pd (II) cation to give a cis - or trans- Pd (II) . In both scenarios, a single transmetalation transition state gives rise to both cis - and trans -species directly, owing to bifurcation after the transition state. The potential subsequent cis - to trans isomerization of the Pd (II) CF 3 was also studied and found to be strongly inhibited by free phosphine, which in turn was experimentally identified to be liberated through displacement by a polar/coordinating solvent from the cis -Pd (II) CF 3 complex. The simulations also revealed how the variation of the Pd-coordination sphere results in divergent product selectivities., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Reported herein is a fully orthogonal olefination, which involves the site- and E-selective coupling of aryl germanes with alkenes, tolerating otherwise widely employed coupling handles such as aromatic (pseudo)halogens (C-I, C-Br, C-Cl, C-F, C-OTf, C-OSO 2 F), silanes and boronic acid derivatives as well as alternative functionalities. This unprecedented [Ge]-based oxidative Heck coupling proceeds at room temperature with high speed (10 min to 2 hours) and operational simplicity owing to its base-free and air-tolerant features., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

We report a site-selective ipso -nitration of aryl germanes in the presence of boronic esters, silanes, halogens, and additional functionalities. The protocol is characterized by operational simplicity, proceeds at room temperature, and is enabled by [Ru(bpy) 3 ](PF 6 ) 2 /blue light photocatalysis. Owing to the exquisite robustness of the [Ge] functionality, nitrations of alternative functional handles in the presence of the germane are also feasible, as showcased herein.

Owing to the unknown correlation of a metal's ligand and its resulting preferred speciation in terms of oxidation state, geometry, and nuclearity, a rational design of multinuclear catalysts remains challenging. With the goal to accelerate the identification of suitable ligands that form trialkylphosphine-derived dihalogen-bridged Ni (I) dimers, we herein employed an assumption-based machine learning approach. The workflow offers guidance in ligand space for a desired speciation without (or only minimal) prior experimental data points. We experimentally verified the predictions and synthesized numerous novel Ni (I) dimers as well as explored their potential in catalysis. We demonstrate C-I selective arylations of polyhalogenated arenes bearing competing C-Br and C-Cl sites in under 5 min at room temperature using 0.2 mol % of the newly developed dimer, [Ni (I) (μ-Br)PAd 2 ( n -Bu)] 2 , which is so far unmet with alternative dinuclear or mononuclear Ni or Pd catalysts.

We report a fully orthogonal C-O bond formation strategy, which involves the selective coupling of arylgermanes with alkyl alcohols (primary, secondary and tertiary) as well as carboxylic acids, tolerating otherwise widely employed coupling handles, such as aromatic (pseudo)halogens (C-I, C-Br, C-Cl, C-F, C-OTf, C-OFs), silanes and boronic acid derivatives. This unprecedented [Ge]-based C-O bond construction is rapid (15 min to few hours reaction time), air-tolerant, operationally simple and mild, as it is base-free and proceeds at room temperature.

The radio-iodination of arenes is investigated from organosilane and organogermane precursors using ipso-electrophilic halogenation (IEH). Discovery of a mild base mediated process allows radio-iodination in HFIP (1,1,1,3,3,3-hexafluoro-2-propanol) of either aryl silane or germane, with germanes being more reactive. Clinical potential of arylgermanes as radio-iodination precursors is demonstrated through the labelling of [ 125 I]IMTO (iodometomidate) and [ 125 I]MIBG (meta-iodobenzylguanidine) thus offering an alternative to radio-iododestannylation processes using non-toxic precursors., (© 2023 Wiley-VCH GmbH.)

While vinyl cyclopropanes are valuable functional groups in drugs or natural products as well as established precursors to trigger a rich variety of synthetic transformations, their reactive nature can make their installation via direct catalytic approaches challenging. We herein present a modular access to (di)vinyl cyclopropanes under very mild conditions and full conservation of stereochemistry, allowing access to the cis or trans cyclopropane- as well as E or Z vinyl-stereochemical relationships. Our protocol relies on air-stable dinuclear Pd I catalysis, which enables rapid (<30 min) and selective access to a diverse range of vinyl cyclopropane motifs at room temperature, even on gram scale., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The departure into unknown chemical space is essential for the discovery of new properties and function. We herein report the first synthetic access to N-trifluoromethylated formamides. The method involves the reduction of bench-stable NCF 3 carbamoyl fluorides and is characterized by operational simplicity and mildness, tolerating a broad range of functional groups as well as stereocenters. The newly made N-CF 3 formamide motif proved to be highly robust and compatible with diverse chemical transformations, underscoring its potential as building block in complex functional molecules., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

While the N-trifluoromethylation of cyclic ureas is of interest for the potential to fundamentally change the properties of these biologically relevant moieties, the single synthetic procedure known to date describing their access only gives 4,4-disubstituted or fused aromatic cyclic N-CF 3 urea derivatives. We herein report an alternative approach to unleash access to the 4-monosubstituted imidazolidinone motif. The strategy relies on straightforward cyclization of readily accessible acyclic ureas, enabled by Ag-catalysis or light-assisted proton coupled electron transfer. The cyclic core is shown to be highly robust and amenable to various derivatizations, such as tandem Ni-catalysis, C-B, C-N, C-C cross couplings or C-H functionalizations, tolerating basic, nucleophilic and/or oxidizing conditions., (© 2022 Wiley-VCH GmbH.)

While the modular construction of molecules from suitable building blocks is a powerful means to more rapidly generate a diversity of molecules than through customized syntheses, the further evolution of the underlying coupling methodology is key to realize widespread applications. We herein disclose a complementary modular coupling approach to the widely employed Suzuki coupling strategy of boron containing precursors, which relies on organogermane containing building blocks as key orthogonal functionality and an electrophilic (rather than nucleophilic) unmasking event paired with air-stable Pd I dimer based bond construction. This allows to significantly shorten the reaction times for the iterative coupling steps and/or to close gaps in the accessible compound space, enabling straightforward access also to iodinated compounds., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

A direct C(sp)-H germylation of terminal alkynes with triethyl germanium hydride is reported. The method is operationally simple and makes use of B(C 6 F 5 ) 3 catalysis in combination with 2,6-lutidine as an organic base. Exclusive selectivity for dehydrogenative germylation of the alkyne over the competing hydrogermylation is observed.

We report the mild activation of carbamoyl azides to the corresponding nitrenes using a blue light/[Ir]-catalyzed strategy, which enables stereospecific access to N -trifluoromethyl imidazolidinones and benzimidazolones. These novel structural motifs proved to be highly robust, allowing their downstream diversification. On the basis of our combined computational and experimental studies, we propose that an electron rebound with the excited metal catalyst is undergone, involving a reduction-triggered nitrogen loss, followed by oxidation to the corresponding carbamoyl nitrene and subsequent C-H insertion.

This Letter discloses the straightforward hydrogermylation of olefins under visible-light organophotoredox-initiated HAT catalysis conditions to yield primary and secondary alkyl germanes at room temperature. The protocol is operationally simple, metal-free, and tolerant of various functional groups. The synthesized alkyl germanes proved to be highly robust toward acidic, basic, or oxidizing conditions and chemical transformations of C sp 2 -GeEt 3 or C sp 2 -BPin functionalities in their presence.

While remote functionalization via chain walking has the potential to enable access to molecules via novel disconnections, such processes require relatively long reaction times and can be in need of elevated temperatures. This work features a remote arylation in less than 10 min reaction time at room temperature over a distance of up to 11 carbons. The unprecedented speed is enabled by the air-stable Pd I dimer [Pd(μ-I)(PCy 2 t Bu)] 2 , which in contrast to its P t Bu 3 counterpart does not trigger direct coupling at the initiation site, but regioconvergent and chemoselective remote functionalization to yield valuable fluorinated 1,1-diaryl alkanes. Our combined experimental and computational studies rationalize the origins of switchability, which are primarily due to differences in dispersion interactions., (© 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Although machine learning bears enormous potential to accelerate developments in homogeneous catalysis, the frequent need for extensive experimental data can be a bottleneck for implementation. Here, we report an unsupervised machine learning workflow that uses only five experimental data points. It makes use of generalized parameter databases that are complemented with problem-specific in silico data acquisition and clustering. We showcase the power of this strategy for the challenging problem of speciation of palladium (Pd) catalysts, for which a mechanistic rationale is currently lacking. From a total space of 348 ligands, the algorithm predicted, and we experimentally verified, a number of phosphine ligands (including previously never synthesized ones) that give dinuclear Pd (I) complexes over the more common Pd (0) and Pd (II) species.

Trialkylamines are widely found in naturally occurring alkaloids, synthetic agrochemicals, biological probes, and especially pharmaceuticals agents and preclinical candidates. Despite the recent breakthrough of catalytic alkylation of dialkylamines, the selective α-C(sp 3 )-H bond functionalization of widely available trialkylamine scaffolds holds promise to streamline complex trialkylamine synthesis, accelerate drug discovery, and execute late-stage pharmaceutical modification with complementary reactivity. However, the canonical methods always result in functionalization at the less-crowded site. Herein, we describe a solution to switch the reaction site through fundamentally overcoming the steric control that dominates such processes. By rapidly establishing an equilibrium between α-amino C(sp 3 )-H bonds and a highly electrophilic thiol radical via reversible hydrogen atom transfer, we leverage a slower radical-trapping step with electron-deficient olefins to selectively forge a C(sp 3 )-C(sp 3 ) bond with the more-crowded α-amino radical, with the overall selectivity guided by the Curtin-Hammett principle. This subtle reaction profile has unlocked a new strategic concept in direct C-H functionalization arena for forging C-C bonds from a diverse set of trialkylamines with high levels of site selectivity and preparative utility. Simple correlation of site selectivity and 13 C NMR shift serves as a qualitative predictive guide. The broad consequences of this dynamic system, together with the ability to forge N-substituted quaternary carbon centers and implement late-stage functionalization techniques, hold potential to streamline complex trialkylamine synthesis and accelerate small-molecule drug discovery.

The expansion of chemical space associated with ubiquitous motifs is key to unleash new properties and functions. In this context, alkynamides, prevalent in numerous drugs and materials, represent an untapped resource. We herein report the first synthetic access to N -trifluoromethyl alkynamides. Our strategy relies on a mild and operationally simple Ni-catalyzed coupling of N -CF 3 carbamoyl fluorides with alkynyl silanes. The synthesized N -CF 3 alkynamides proved to be highly robust and readily functioned as a platform to unlock access to valuable derivatives, such as N -CF 3 decorated alkenyl amides, oxindoles, or quinolones, all of which were inaccessible to date.

The direct C-H germylation of heteroarenes, arenes, and benzylic C-H bonds promoted by lithium tetramethylpiperidide (LiTMP) is reported. The method is rapid, selective, and operationally simple, consisting of direct addition of all reagents at room temperature (one-pot procedure). The synthetic utility of these newly accessed aryl germanes as viable coupling partners in Pd catalysis is also showcased.

We report an operationally simple, selective, and transition-metal-free germylation of arenes and styrenes at room temperature, using a robust and bench-stable Ge source (R 3 Ge-SiR 3 ) and dibenzothiophenium salts as enabling intermediates. The first direct engagement in cross-coupling of the newly made E -alkenyl germanes is also presented, allowing the chemoselective arylation under air-tolerant nanoparticle catalysis.

We report a remote functionalization strategy, which allows the Z -selective synthesis of silyl enol ethers of (hetero)aromatic and aliphatic ketones via Ni-catalyzed chain walking from a distant olefin site. The positional selectivity is controlled by the directionality of the chain walk and is independent of thermodynamic preferences of the resulting silyl enol ether. Our mechanistic data indicate that a Ni (I) dimer is formed under these conditions, which serves as a catalyst resting state and, upon reaction with an alkyl bromide, is converted to [Ni (II) -H] as an active chain-walking/functionalization catalyst, ultimately generating a stabilized η 3 -bound Ni (II) enolate as the key selectivity-controlling intermediate.

Pd-catalyzed cross-coupling reactions of aryl diazonium salts are generally assumed to proceed via cationic Pd II intermediates which in turn would be highly reactive in the subsequent transmetalation step. Contrary to this belief, we herein report our observation and rationalization of opposing reactivities of ArN 2 + in Suzuki (=effective) and Stille (=ineffective) cross-couplings in MeOH. Our systematic experimental and computational studies on the roles of transmetalating agent, solvent, base and the likely involvement of in situ formed diazoether derivatives challenge the currently accepted mechanism. Our data suggest that the observed solvent dichotomy is primarily due to Pd II -methoxy intermediates being formed, which are unreactive with arylstannanes, but highly reactive with arylboronic acids, complementing the Suzuki "Pd-oxy" mechanism with the direct demonstration of transmetalation of a Pd II -alkoxy complex. Lewis acids were found to circumvent this reactivity divergence, promoting efficient couplings regardless of the employed conditions or coupling partners., (© 2021 Wiley-VCH GmbH.)

Dinuclear Pd I complexes have found widespread applications as diverse catalysts for a multitude of transformations. Initially their ability to function as pre-catalysts for low-coordinated Pd 0 species was harnessed in cross-coupling. Such Pd I dimers are inherently labile and relatively sensitive to oxygen. In recent years, more stable dinuclear Pd I -Pd I frameworks, which feature bench-stability and robustness towards nucleophiles as well as recoverability in reactions, were explored and shown to trigger privileged reactivities via dinuclear catalysis. This includes the predictable and substrate-independent, selective C-C and C-heteroatom bond formations of poly(pseudo)halogenated arenes as well as couplings of arenes with relatively weak nucleophiles, which would not engage in Pd 0 /Pd II catalysis. This Minireview highlights the use of dinuclear Pd I  complexes as both pre-catalysts for the formation of highly active Pd 0 and Pd II -H species as well as direct dinuclear catalysts. Focus is set on the mechanistic intricacies, the speciation and the impacts on reactivity., (© 2020 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

We report a new air-stable Pd I dimer, [Pd(μ-I)(PCy 2 t Bu)] 2 , which triggers E-selective olefin migration to enamides and styrene derivatives in the presence of multiple functional groups and with complete tolerance of air. The same dimer also triggers extremely rapid C-C coupling (alkylation and arylation) at room temperature in a modular and triply selective fashion of aromatic C-Br, C-OTf/OFs, and C-Cl bonds in poly(pseudo)halogenated arenes, displaying superior activity over previous Pd I dimer generations for substrates that bear substituents ortho to C-OTf., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

Since the advent of metal-catalyzed cross-coupling technology more than 40 years ago, the field has grown to be ever-increasingly enabling, yet the employed coupling partners are largely still those that were originally employed in the context of Pd-catalyzed cross-coupling, namely, arylboronic esters/acids, aryl silanes, aryl stannanes, or organometallic reagents (RMgX, RZnX). Aryl germanes have little precedent in the literature; they were historically explored in the context of Pd 0 /Pd II -catalyzed cross-coupling reactions but were found to be much less reactive than the already established reagents. Consequently, few efforts were made by the community on their further mechanistic or synthetic exploration.In 2019, our group described trialkyl aryl germanes as robust, convenient, and nontoxic reagents. Although structurally similar to trialkyl aryl stannanes or silanes, the GeEt 3 site does not engage in the traditional transmetalation mode of Pd II complexes. Our studies instead provided strong support for an unprecedented and orthogonal reactivity of organogermanes that follows electrophilic aromatic substitution (S E Ar)-type reactivity. This mode of bond activation allowed us to devise a number of synthetic strategies in which the Ge functionality was for the first time more reactive and exclusively functionalized in preference over several of the established coupling partners ( e.g. , silanes, boronic acids/esters, halogens).Within the past year we have showcased the unique reactivity of organogermanes in C-C and C-X bond-forming transformations. Because of the exquisite mode of bond activation, the new strategies offer access to complementary chemical transformations, tolerating other cross-coupling enabling functionalities, and allow for their further downstream diversification. We have for instance demonstrated that organogermanes can be coupled efficiently with aryl halides under Pd nanoparticle conditions with tolerance of all other established cross-coupling partners, while under homogeneous Pd 0 /Pd II catalysis all of the other established groups can be functionalized preferentially over the Ge functionality. We similarly were able to harness this orthogonal reactivity mode in oxidative gold catalysis, where organogermanes proved to be more reactive than the established silanes or boronic esters. We have also developed an orthogonal approach for metal-free halogenation of organogermanes with convenient halogenation agents, offering access to the chemo- and regioselective installation of valuable halide motifs in the presence of alternative groups that can also engage in electrophilic halogenations.In this Account, we wish to provide an overview of (i) the historic versus current reactivity findings and synthetic utility of organogermanes, (ii) the current state of mechanistic understanding of their reactivity, and (iii) the synthetic repertoire and ease of installing the germanium functionality in organic molecules.

While halogenation is of key importance in synthesis and radioimaging, the currently available repertoire is largely designed to introduce a single halogen per molecule. This report makes the selective introduction of several different halogens accessible. Showcased here is the privileged stability of nontoxic aryl germanes under harsh fluorination conditions (that allow selective fluorination in their presence), while displaying superior reactivity and functional-group tolerance in electrophilic iodinations and brominations, outcompeting silanes or boronic esters under rapid and additive-free conditions. Mechanistic experiments and computational studies suggest a concerted electrophilic aromatic substitution as the underlying mechanism., (© 2020 The Authors. Published by Wiley-VCH GmbH.)

Selective C sp 2 -C sp 2 couplings are powerful strategies for the rapid and programmable construction of bi- or multiaryls. To this end, the next frontier of synthetic modularity will likely arise from harnessing the coupling space that is orthogonal to the powerful Pd-catalyzed coupling regime. This report details the realization of this concept and presents the fully selective arylation of aryl germanes (which are inert under Pd 0 /Pd II catalysis) in the presence of the valuable functionalities C-BPin, C-SiMe 3 , C-I, C-Br, C-Cl, which in turn offer versatile opportunities for diversification. The protocol makes use of visible light activation combined with gold catalysis, which facilitates the selective coupling of C-Ge with aryl diazonium salts. Contrary to previous light-/gold-catalyzed couplings of Ar-N 2 + , which were specialized in Ar-N 2 + scope, we present conditions to efficiently couple electron-rich, electron-poor, heterocyclic and sterically hindered aryl diazonium salts. Our computational data suggest that while electron-poor Ar-N 2 + salts are readily activated by gold under blue-light irradiation, there is a competing dissociative deactivation pathway for excited electron-rich Ar-N 2 + , which requires an alternative photo-redox approach to enable productive couplings., (© 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

Reported herein is the first efficient strategy to synthesize a broad range of unsymmetrical N-CF 3 hydrazines, which served as platform to unlock numerous currently inaccessible derivatives, such as tri- and tetra-substituted N-CF 3 hydrazines, hydrazones, sulfonyl hydrazines, and valuable N-CF 3 indoles. These compounds proved to be remarkably robust, being compatible with acids, bases, and a wide range of synthetic manipulations. The feasibility of RN(CF 3 )-NH 2 to function as a directing group in C-H functionalization is also showcased., (© 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

While aryl germanes have recently found usage as coupling partners in powerful catalytic applications, the synthetic access to this promising functionality is currently limited. This report details the straightforward synthesis of functionalized aryl triethylgermanes via formal C-H functionalization. Building on the concept of directing-group-free and site-selective C-H functionalization of arenes to thianthrenium salt intermediates, we showcase their efficient couplings with triethylgermane (Et 3 Ge-H) at room temperature, which was enabled by the air- and moisture-stable Pd(I) dimer, [Pd(μ-I)(P t Bu 3 )] 2 . The method tolerates numerous functional groups, including valuable (pseudo)halides.