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A new catalyst-free protocol for aminomethylamination of o-hydroxystyrenes with simple aminals is described. This direct and operationally simple method provides a fundamentally novel and rapid approach for the synthesis of 1,3-diamines. This novel reaction occurs under mild reaction conditions and provides a fundamentally unique and efficient strategy for the synthesis of 1,3-diamines with good to excellent yields. [ABSTRACT FROM AUTHOR]

Various 1,2-, 1,3-, and 1,4-substituted cyclic iodides or bromides undergo highly diastereoselective cross-couplings (diastereoselectivity (dr) up to 99:1) with a range of alkynylzinc pivalates, using CoCl2 (20 mol %) and trans-N,N,N',N'-tetramethylcyclohexane-1,2-diamine as a catalytic system. [ABSTRACT FROM AUTHOR]

The electro-oxidative generation of diaza-oxyallyl cation and its application to the synthesis of diamine motifs has been explored. Because of the synergistic combination of anodic and cathodic reactions, the current electrochemical method not only avoids the use of a stoichiometric amount of chemical oxidant but also eliminates the need for supporting electrolyte and external base required for effective oxidation. [ABSTRACT FROM AUTHOR]

The scope of enantioselective (4 + 2)-cycloaddition reactions has been expanded to include reactive olefinic components that are equivalents of three inoperable and unstable ethylene derivatives: 1-hydroxy-2-aminoethylene, 1,2-diaminoethylene, and β-aminoacrylic acid. In this way, a variety of otherwise unavailable functionalized (4 + 2)-cycloadducts have been synthesized from 1,3-dienes with high enantioselectivity (92-98%) and in good yields. The research leading up to this synthetic advance has also produced some surprising insights on reactivity and positional selectivity in catalytic enantioselective (4 + 2)-cycloaddition. [ABSTRACT FROM AUTHOR]

The amination of racemic secondary and tertiary allylic trichloroacetimidates possessing β-nitrogen substituents and proximal nitrogen-containing heterocycles, via chiral diene-ligated rhodium-catalyzed dynamic kinetic asymmetric transformations (DYKAT), provides branched allylic 1,2-diamines with high enantioselectivity. The catalytic system can be applied to the synthesis of 1,2-diamines possessing two contiguous stereocenters with excellent diastereoselectivity. Furthermore, the nitrogen-containing heterocycles suppress competing vinyl azirdine formation, allowing for the high enantioselective syntheses of 1,2-diamines possessing tertiary and quaternary centers. [ABSTRACT FROM AUTHOR]

The 1,3-diamine motif appears in numerous complex molecules, yet there are few methods for the stereoselective construction of this moiety. Herein, we demonstrate a stereocontrolled synthesis of 1,3-diamines, which bear up to three contiguous stereogenic centers, through benzylic ring-opening of aziridines with 2-azaallyl anion nucleophiles. Reactions proceed efficiently (yield up to 95%), diastereoselectively (dr up to >20:1), site selectively, and enantiospecifically to deliver products with differentiated amino groups. [ABSTRACT FROM AUTHOR]

The previously unknown 5-spirocyclohexylisoimidazole has been made efficiently and simply by reaction of ammonia, glyoxal hydrate, and cyclohexanone. It is a very useful precursor for the diastereocontrolled synthesis of many C2-symmetric 1,2-diamines, a class which is important for the generation of a variety of C2-symmetric reagents and catalysts for enantioselective synthesis. [ABSTRACT FROM AUTHOR]

The DITIPIRAM (8-propyldithieno[3,2-b:2',3'-e]pyridine-3,5-diamine)-based receptors 11 and 12 were readily synthesized, and their anion-binding properties were studied both in solution and in the solid-state. 1H NMR titrations revealed that receptor 12 equipped with two phenyl-urea groups preferentially binds carboxylates, even in the highly competitive DMSO-d6/CD3OH solvent mixture. X-ray analysis showed that receptor 12 exhibited great complementarity for benzoate, which is cooperatively bound by the means of four highly directional hydrogen bonds from the two urea groups. Comparison with the most effective acyclic receptors based on a structurally related rigid carbazole platform demonstrates that the DITIPIRAM motif provides a better suited geometry in the binding pocket, and consequently stronger anion binding. [ABSTRACT FROM AUTHOR]

A two-step reaction sequence for the highly stereodivergent construction of 1,3-diamines with three continuous stereocenters is reported. This novel method enables the controlled synthesis of any given diastereomer of the 1,3-diamine scaffold from a simple set of starting materials in a highly modular manner. The disclosed approach is based on the reaction of an enamide with an in situ generated N-acylimine followed by a subsequent trapping of the generated intermediate with a suitable nucleophile. By careful choice of starting materials, reagents, and reaction conditions, each stereocenter can be constructed in a highly selective fashion. [ABSTRACT FROM AUTHOR]

We have developed a one-pot synthetic method for producing 1,2-diamines from easily prepared and commercially available precursors through a formal umpolung process. Our method utilizes an efficient [3 + 2] cycloaddition as the key step in forming substituted 1,2-diamines in moderate to high yields. These resulting compounds can undergo subsequent transformations, demonstrating their utility as synthetic building blocks for more complex scaffolds. Finally, we propose a reasonable mechanism for this transformation using density functional theory modeling, justifying the experimental observations.

The catalytic construction of benzimidazoles using CO2 as a carbon source represents a facile and sustainable approach to obtaining these valuable compounds. Herein, we describe the B(C6F5)3-catalyzed synthesis of benzimidazoles via cyclization of o-phenylenediamines with CO2 and PhSiH3. This metal-free catalytic route achieves the desired products in high yield under convenient reaction conditions and is applicable to a broad substrate scope. A plausible mechanism for the reaction involving a frustrated Lewis pair pathway is proposed based on spectroscopic characterization (e.g., 13C NMR) of the reaction intermediates. [ABSTRACT FROM AUTHOR]

The first asymmetric cycloaddition of nonstabilized azomethine ylide and N-sulfinylimines is presented. In reactions with aryl-alkyl and heteroaryl-alkyl ketimines, excellent diastereoselectivities and good yields are obtained in all cases, regardless of the electronic character of the substituents at the aromatic rings. Moreover, the cycloadducts obtained can easily be deprotected in acid media, giving access to free 1,2-diamines which are prevalent in many natural and pharmaceutical products. [ABSTRACT FROM AUTHOR]

A diastereodivergent catalytic asymmetricMichael addition of 2-oxindolesto α,β-unsaturated ketones has been successfully developedwith two complementary chiral diamine catalysts, affording chiral3,3-disubstituted oxindoles with two adjacent chiral centers. Diastereodivergencehas been realized through modifying substrates and utilizing differentcatalysts. Either anti-or syn-configuredproducts possessing vicinal quaternary and tertiary stereogenic centerswere produced with high enantioselectivities. [ABSTRACT FROM AUTHOR]

Radical addition of various xanthatesto N,N′-diacylimidazol-2-oneoccurs readily to give protected1,2-diamines. The imide group stabilizes the adduct radical sufficientlyto enable a second addition to unactivated alkenes. In some cases,the addition product could be converted into an indoline, a tetralone,or further added to an indole. Regioselective removal of one acylgroup could also be accomplished. [ABSTRACT FROM AUTHOR]

Thechiral pool-derived 1,1′-ditosyl-2,2′-biaziridinehas been established as a valuable building block for the divergentsynthesis of enantiopure vicinal diamines. Efficient procedures forthe regioselective ring opening of the biaziridine with oxygen, sulfur,nitrogen, and carbon nucleophiles are described. The strategic useof nucleophiles bearing pendant functionality allows further elaborationof the acyclic products to a variety of 2,2′-bicyclic-embeddeddiamines. Desymmetrization of the biaziridine has also been accomplishedvia the selective monoaddition of organocuprates. [ABSTRACT FROM AUTHOR]

An asymmetric hydrogenation of stericallyhindered β,β-disubstitutedenones has been well-established by using a ruthenium complex composedof an achiral diphosphane and a chiral diamine as catalyst, whereinthe carbonyl group was selectively hydrogenated to give a wide rangeof chiral allylic alcohols with high levels of enantioselectivityand complete chemoselectivity. [ABSTRACT FROM AUTHOR]

In this paper an aminative umpolungsynthesis of aryl vicinal diaminesfrom aldehydes and N-Ts imines is described. Electrophilicaromatic aldehydes were smoothly converted into delocalized 2-azaallylanionsvia condensation with 2,2-diphenylglycine in methanol and subsequentdecarboxylation in THF and underwent further reaction with N-Ts imines to give a variety of 1,2-diamine derivativesin good yields with high syn/antidiastereoselectivity. [ABSTRACT FROM AUTHOR]

Nitroepoxidesare easily transformed into 1,4-diamino heterocyclessuch as quinoxalines and pyrazines by treatment with 1,2-benzenediaminesand ammonia, respectively. Additionally, related saturated heterocycles,such as piperazines and tetrahydroquinoxalines, can be accessed bytreatment with 1,2-diamines and a reducing agent. These transformationsare efficient, provide access privileged, bioactive structures, andproduce minimal waste. [ABSTRACT FROM AUTHOR]

The sturdy chelation of 1,2-diamines and transition-metals would retard or even interrupt the routine catalytic cycles. In the amidation and asymmetric reductive amination (ARA) cascade reactions of diamines and ketoesters, we deployed sets of additives to ensure a smooth transformation catalyzed by the complexes of rhodium and versatile and highly modular phosphoramidite-phosphine ligands. The tunability of the ligands was fully exploited to accommodate various diamines and α-ketoesters for the efficient synthesis of chiral 3,4-dihydroquinoxalinones.

Vicinal diamines are a common motif found in biologically active molecules. The hydroamination of allyl amine derivatives is a powerful approach for the synthesis of substituted 1,2-diamines. Herein, the rhodium-catalyzed hydroamination of primary and secondary allylic amines using diverse amine nucleophiles, including primary, secondary, acyclic, and cyclic aliphatic amines to access a wide range of unsymmetrical vicinal diamines, is presented. The utility of this methodology is further demonstrated through the rapid synthesis of several bioactive molecules and analogs.

The first total synthesis of the Evodia rutaecarpaderived natural product dievodiamine is described. The convergent synthesis was performed without protecting groups, delivering a route that is short and high yielding and uses limited chromatography. Key steps include organometallic addition into a DHED adduct and the Stille coupling of two advanced intermediates to complete the synthesis. [ABSTRACT FROM AUTHOR]

A facile one-pot synthesis of 3-trifluoromethylated piperazin-2-ones has been achieved by the treatment of trifluoromethyl 2-bromo enones with N,N′-disubstituted ethylenediamines in trifluoroethanol. The mechanism of this unexpected reaction is discussed in terms of multistep processes involving formation of captodative aminoenone as a key intermediate. The unique influence of trifluoromethyl group on the reaction path was demonstrated. [ABSTRACT FROM AUTHOR]

Both, cis- and trans-3,4-disubstituted thiadiazolidines 5and 6can enantioselectively be obtained from thiadiazoles 2which, in turn, are efficiently prepared from the respective 1,2-diketone by an improved protocol. An asymmetric ruthenium-catalyzed transfer hydrogenation followed by a diastereoselective hydride addition furnishes exclusively the cis-isomers 5which, under acidic conditions, undergo a novel isomerization into the trans-isomers 6. These cyclic sulfamides can be transformed into 1,2-diamines as well as 2,3-diamino acids. [ABSTRACT FROM AUTHOR]

A general, high yielding method for the synthesis of 1,2-diamine derivatives is described that capitalizes on selective, rhodium-catalyzed C–H insertion of hydroxylamine-based sulfamate esters. The resulting Troc-protected oxathiadiazinane heterocycles are easily modified and can be reduced under the mild action of NaI to afford differentially substituted diamine products. This technology offers a number of salient improvements over related C–H and π-bond amination tactics for diamine synthesis. [ABSTRACT FROM AUTHOR]

The rapid and efficient construction of complex chiral bicyclic amines is possible using a novel alkene diamination reaction. Electrophilic iodinating agents promote the intramolecular anti-selective diamination of alkenes and allow the efficient synthesis of chiral amines such as trans-bipyrrolidines. [ABSTRACT FROM AUTHOR]

A nickel-catalyzed oxidative coupling of zinc amides with organomagnesium compounds selectively produces diarylamines under mild reaction conditions, with tolerance for chloride, bromide, hydroxyl, ester, and ketone groups. A diamine is bis-monoarylated. A bromoaniline undergoes N-arylation followed by Kumada–Tamao–Corriu coupling in one pot. The reaction may proceed via oxidatively induced reductive elimination of a nickel species. [ABSTRACT FROM AUTHOR]

We have developed a hybrid system of metal/Brønsted acid relay catalysis for the intramolecular double hydroarylation and cationic cyclization of diyne diethers and diamines to give 4,4′-bi(2H-chromene), bi(2H-quinoline), and dioxafluoranthenes starting from 2,4-diyne-1,6-diethers and diamines in one reaction vessel under mild conditions. [ABSTRACT FROM AUTHOR]

N-Substituted phenoxazines and related aza analogs have been prepared from N-acetylated aryloxy anilides by transition-metal-free, base-catalyzed cyclization reactions. In the presence of a mixture of 10 mol % of N,N′-dimethylethylenediamine (DMEDA) and 2 equiv of K2CO3in toluene at 135 °C the products are obtained in high yields. [ABSTRACT FROM AUTHOR]

An efficient procedure for the preparation of naphthalene-1,3-diamine derivatives by copper-catalyzed haloalkynes with amines has been reported. The reaction was supposed to proceed through a coupling reaction followed by the dimerization of ynamines. [ABSTRACT FROM AUTHOR]

The four stereoisomers of protected cyclobutane-1,2-diamine have been prepared in an enantio- and diastereocontrolled manner through stereodivergent synthetic routes starting from a half-ester as a common chiral precursor. Orthogonal protection allows the chemoselective manipulation of both amino groups as shown in this work. [ABSTRACT FROM AUTHOR]