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Piperazines constitute an important structural feature of many pharmaceuticals. For the discovery of new drugs, the ability to modify the lead compound's structure is crucial. Herein, we provide an efficient method for the synthesis of chiral 2,3,5-trisubstituted piperazine structures. Our route enables the synthesis of several novel chiral aryl aziridinyl ketones that could be converted into aziridine-fused bicyclic imines. The reduction of these imines and the nucleophilic ring-opening reaction of the aziridine ring allowed us to synthesize highly functionalized piperazine derivatives. [ABSTRACT FROM AUTHOR]

A general and atom-efficient synthesis of quinoline-C2-substituted β-hydroxyarylethylamino derivatives was achieved by copper-catalyzed [3+3]-cycloaddition reaction of N -oxide with N -Ts aziridines. Notably, temperature has a huge impact on this transformation as evidenced by the fact that, at 80 °C, exclusively the [3+3] cycloadduct was isolated whereas, at elevated temperature (140 °C), it has been converted into the aminated product with good yield. Notably, there is no byproduct in the overall process. The use of base-free conditions, excellent site selectivity, and good functional group tolerance are the important features of the process. [ABSTRACT FROM AUTHOR]

Keywords: photocatalysis; Barbier reaction; aziridines; azetidines; C-N bond cleavage EN photocatalysis Barbier reaction aziridines azetidines C-N bond cleavage 1385 1390 6 07/11/23 20230725 NES 230725 Graph C-C bond-formation processes are an essential class of reactions for the construction of the skeletons of organic compounds. Photocatalysis, Barbier reaction, aziridines, azetidines, C-N bond cleavage After the reduction, the radical-anion intermediate B I b smoothly undergoes C-N bond cleavage to deliver the benzyl radical intermediate B II b . [72] Here, we report a visible-light photocatalytic Barbier-type reaction of aziridines and azetidines with nonactivated aldehydes through reductive cleavage of C-N bonds [75] (Scheme 1 C). [Extracted from the article]

A one-pot asymmetric aminoarylation reaction has been executed for the synthesis of trans -4-amino-5-aryltetrahydrobenzo[ c ]azepines with excellent diastereo- and enantioselectivity (dr > 99: 1; ee ≤97%). The reaction progresses through aziridination of prochiral N -tosyl- N -cinnamylbenzylamines, followed by an intramolecular 7-endo-tet Friedel–Crafts cyclization of the tethered aziridines generated in situ, where the combination of Cu(OTf)2 as a catalyst and PhINNs as a nitrene source was found to be effective. A chiral indenyl bis(oxazoline) was shown to be an efficient ligand for the catalytic enantioselective version of this one-pot transformation. This 7-endo-tet cyclization is contrary to the Baldwin cyclization rules. [ABSTRACT FROM AUTHOR]

Herein a bimetallic radical redox-relay strategy is employed to generate alkyl radicals under mild conditions with titanium(III) catalysis and terminated via hydrogen atom transfer with cobalt(II) catalysis to enact base-free isomerizations of N -Bz aziridines to N -Bz allylic amides. This reaction provides an alternative strategy for the synthesis of allylic amides from alkenes via a three-step sequence to accomplish a formal transpositional allylic amination. [ABSTRACT FROM AUTHOR]

Homologation strategies provide highly versatile tools in organic synthesis for the introduction of a CH2 group into a given carbon skeleton. The operation can result in diverse structural motifs by tuning of the reaction conditions and the nature of the homologating agent. In this Account, concisely contextualizing our work with lithium carbenoids (LiCH2 X, LiCHXY etc) for homologating carbon-centered electrophiles, we focus on the assembly of three-membered cycles featuring fluorinated substituents. Two illustrative case studies are considered: (1) the development and employment of fluorinated carbenoids en route to rare α-fluoroepoxides and aziridines, and (2) the installation of up to halomethylenic groups on trifluoroimidoylacetyl chlorides (TFAICs) for preparing CF3-containing halo- and halomethylaziridines. Collectively, we demonstrate that the initial homologation event generated by the installation of the carbenoid, upon modulation of the conditions, serves as a tool for creating fluorinated building blocks in a single operation. [ABSTRACT FROM AUTHOR]

Cycloaddition reactions of aziridines with dipolarophiles under traditional thermal or photochemical conditions entail destructive routes to form reactive intermediates such as an azomethine ylide. This article highlights a recent study that demonstrates a cycloaddition reaction of aziridine induced by mechanical force. Experimental results suggest that the force-induced cycloaddition of aziridine with dimethyl acetylenedicarboxylate as a dipolarophile does not seem to involve an ylide, with implications for a possible new reaction route. 1 Rivalry between Aziridine and Epoxide 2 Mechanochemically Responsive Polymers 3 Aziridine Mechanophore 4 Concluding Remarks and Outlook [ABSTRACT FROM AUTHOR]

A mild and efficient palladium-catalyzed [3+2] cycloaddition of vinylaziridine and indane-1,3-diones has been realized. The resulting spiro-pyrrolidines were provided in excellent yields and, with the introduction of the leucine-derived phosphine ligand, moderate to good enantio-- and diastereoselectivities. [ABSTRACT FROM AUTHOR]

This work details the synthesis of 22 new chiral VANOL ligands that differ by the nature of the substituent in the 3- and 3′-positions of the ligand. These ligands were incorporated into boroxinate catalysts that were used to screen the catalytic asymmetric aziridination of benzhydryl imines with ethyl diazoacetate. Each catalyst was screened in the reaction of imines generated from benzaldehyde and cyclohexanecarboxaldehyde and some with 4-nitro- and 4-methoxybenzaldehyde. In addition, the first report of the effect of the ester substituent of the diazoacetate ester on the asymmetric induction in these aziridination reactions is presented. The first X-ray structure of a boroxinate catalyst generated from a VANOL-derived ligand is also reported. [ABSTRACT FROM AUTHOR]

The catalytic asymmetric ring-opening transformations of aziridines represent an important strategy for the construction of various chiral nitrogen-containing molecular architectures. This short review covers the progress achieved in the catalytic asymmetric transformation of racemic aziridines, focusing on the catalytic strategies employed for each different type of such aziridines. 1 Introduction 2 Reaction of Racemic 2-Vinylaziridines 3 Reaction of Racemic 2-Alkylaziridines 3.1 Regiodivergent Parallel Kinetic Resolution 3.2 Kinetic Resolution 4 Reaction of Racemic 2-(Hetero)arylaziridines 4.1 Kinetic Resolution 4.2 Enantioconvergent Transformation 5 Reaction of Racemic Donor–Acceptor-Type Aziridines 6 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

A simple strategy to access a wide range of substituted oxime amino ethers in good to high yields via Lewis acid catalyzed SN 2-type ring opening of activated aziridines with aryl aldehyde oximes is reported. [ABSTRACT FROM AUTHOR]

A method for efficient and mild synthesis of diarylmethylamine scaffold, via Lewis acid catalyzed Friedel–Crafts reaction of donor-–acceptor aziridines with N , N -dialkylanilines to afford a biologically important diarylmethylamine derivatives in high yields (up to 88%), is presented. This reaction is suitable for the synthesis of various diarylmethylamine derivatives and has a broad scope for electron-rich arenes, including dimethoxybenzene. [ABSTRACT FROM AUTHOR]

Over the past decades, phase-transfer catalysis (PTC), generally based on numerous chiral quaternary ammonium salts, has been recognized as a powerful and versatile tool for organic synthesis in both industry and academia. In sharp contrast, PTC involving chiral phosphonium salts as the catalysts is insufficiently developed. Recently, our group realized the first enantioselective aza-Darzens reaction for preparing tri- and tetrasubstituted aziridine derivatives under bifunctional phosphonium salt catalysis. This article briefly discusses the recent development in asymmetric reactions (mainly including nucleophilic additions and cyclizations) promoted by chiral quaternary phosphonium salt catalysts. We expect that more catalytic asymmetric reactions will be developed on the basis of such new phase-transfer catalytic systems in the near future. [ABSTRACT FROM AUTHOR]

In this account, we provide an overview of some recent advances in electrophilic amination methodologies that have been developed in the Kürti group over the last seven years. Our group's focus has been to develop novel amination methodologies that directly yield N -unprotected amine products. 1 Introduction 2 Amination of Boronic Acids 3 Aziridination of Unactivated Olefins 4 Rhodium-Catalyzed C–H Amination of Arenes 5 Synthesis of Carbazoles 6 Amination of Aryl- and Alkylmetals 7 Doubly Electrophilic N -Linchpin Reagents 8 Aza-Rubottom Oxidation of Silyl Enol Ethers 9 Summary [ABSTRACT FROM AUTHOR]

The asymmetric synthesis of (3R,5S)-5-(aminomethyl)-3-(4- methoxyphenyl)dihydrofuran-2(3H)-one, as the most potent selective inactivator of monoamine B, was successfully achieved by applying a newly developed synthetic method toward the key γ-aminomethyl-γ- lactone via intramolecular aziridine ring opening in 63% overall yield from a commercial starting material. [ABSTRACT FROM AUTHOR]

A ß-monofluoromethylated vinyl sulfonium salt, prepared in situ from a precursor γ-fluoro ß-acetoxypropyl sulfonium salt under mild basic conditions, reacted with a lvariety of active methylene compounds or a primary sulfone amide under basic conditions to provide the corresponding monofluoromethylated three-membered rings in good-to-excellent yields. This new sulfonium reagent should permit easy access to a variety of important monofluoromethylated organic compounds. [ABSTRACT FROM AUTHOR]

3-Hydroxy-4-(trifluoromethyl)azetidin-2-ones were synthesized from the corresponding 3-benzyloxy-β-lactams and successfully transformed into new 3-chloro-4-(trifluoromethyl)azetidin-2-one building blocks. The latter chlorides were shown to be eligible precursors for the construction of CF3-containing aminopropanes, 1,3-oxazinanes, 1,3-oxazinan-2-ones, and aziridines. In addition, 3-hydroxy-4-(trifluoromethyl) azetidin-2-ones proved to be interesting substrates for the synthesis of novel 3-[2,2,2-trifluoro-1-(arylamino)ethyl]-1,4-dioxan-2-ones via intramolecular cyclization of 3-(2-hydroxyethoxy)-β-lactam intermediates. [ABSTRACT FROM AUTHOR]

Small heterocycles, such as epoxides, aziridines, and oxetanes are among the most useful building blocks in organic synthesis. Through electrophilic ring opening of these molecules, various electrophilic functional groups can be installed, which cannot be achieved via classic nucleophilic ring-opening reactions. In this review, the developments of electrophilic ring opening of small heterocycles are surveyed and organized according to the types of metal promoters. 1 Introduction 2 Electrophilic Ring Opening of Small Heterocycles Using Stoichiometric Metals 2.1 Lithium-Mediated Electrophilic Ring Opening of Epoxides and Oxetanes 2.2 Chromium-Mediated Electrophilic Ring Opening of Vinyl Epoxides 2.3 Tin-Mediated Electrophilic Ring Opening of Vinyl Epoxides 2.4 Samarium-Mediated Electrophilic Ring Opening of Vinyl and Alkynyl Epoxides 2.5 Titanium-Mediated Electrophilic Ring Opening of Epoxides 2.6 Platinum, Palladium, and Nickel-Mediated Electrophilic Ring Opening of 1,1-Dimethyl Ethylene Oxide 3 Catalytic Electrophilic Ring Opening of Small Heterocycles 3.1 Titanium-Catalyzed Electrophilic Ring Opening of Epoxides 3.2 Palladium-Catalyzed Electrophilic Ring Opening of Vinyl and Alkynyl Small Heterocycles 3.3 Iron-Catalyzed Electrophilic Ring Opening of Oxetanes 3.4 Scandium-Catalyzed Electrophilic Ring Opening of Vinyl Epoxides 3.5 Iridium-Catalyzed Electrophilic Ring Opening of 2-Methyl 2-Vinyloxiranes 3.6 Nickel-Catalyzed Electrophilic Ring Opening of Epoxides and Aziridines 3.7 Nickel-Titanium-Cocatalyzed Electrophilic Ring Opening of Epoxides 4 Summary [ABSTRACT FROM AUTHOR]

This review highlights recent achievements in the transformations of 2-acylaziridines toward the synthesis of cyclic and acyclic nitrogen- containing compounds. The influence of a carbonyl group on reaction selectivity is discussed. 1 Introduction 2 Reactions via C-C Bond Cleavage 3 Reactions via C-N Bond Cleavage 3.1 Reactions Starting with the Aziridine Ring Opening 3.2 Reactions Starting at the Carbonyl Group 4 Conclusion [ABSTRACT FROM AUTHOR]

Pactamycin, a potent antitumor and antimicrobial antibiotic, possesses a densely functionalized cyclopentane core structure. This paper describes the concise synthesis of an advanced intermediate for synthesizing the enantiomer of pactamycin that contains the cyclopentane skeleton bearing all the necessary amino functions with correct stereochemistries. [ABSTRACT FROM AUTHOR]

A Michael-induced ring-closure (MIRC) strategy allowing the synthesis of 2-substituted aziridine-2-carboxylic esters is presented. A broad spectrum of nucleophiles can be applied, leading to large diversity of products which can be subjected to further structural modifications. Diastereoselective ring closure is observed in the case of chiral substrates. [ABSTRACT FROM AUTHOR]

In this study, an efficient ring rearrangement of 2-[2-(1-pyrrolin-2-yl)alkyl]aziridines, prepared from 2-(bromomethyl)aziridines, toward novel trans- and cis-3-aminomethyl-substituted pyrrolizidines was developed. To that end, addition of In(OTf)3 as an appropriate Lewis acid catalyst resulted in the formation of intermediate pyrrolizidinium salts via regioselective aziridine ring opening, which were then trapped by a hydride or cyanide nucleophile. Column chromatographic purification allowed the isolation of the major trans-isomers, exclusively. [ABSTRACT FROM AUTHOR]

N-H-Aziridines undergo efficient ring-opening reactions with aromatic and aliphatic thiols in liquid sulfur dioxide as reaction medium. Due to the Lewis acidic nature of SO2, these reactions do not require any other catalytic additives. The expected β-alkyl/arylthioamines (β-amino thioethers) are obtained with excellent β-regioselectivity. The developed reaction conditions are compatible with chiral starting materials the enantiomeric purity of which is conserved in the corresponding products. This method is also useful for direct synthesis of carbohydrate-amino acid conjugates and 2-iminothiazolidine derivatives. [ABSTRACT FROM AUTHOR]

N-H-Aziridines undergo efficient ring-opening reactions with aromatic and aliphatic thiols in liquid sulfur dioxide as reaction medium. Due to the Lewis acidic nature of SO2, these reactions do not require any other catalytic additives. The expected β-alkyl/arylthioamines (β-amino thioethers) are obtained with excellent β-regioselectivity. The developed reaction conditions are compatible with chiral starting materials the enantiomeric purity of which is conserved in the corresponding products. This method is also useful for direct synthesis of carbohydrate-amino acid conjugates and 2-iminothiazolidine derivatives. [ABSTRACT FROM AUTHOR]

An efficient and scalable synthesis of the antiepileptic drug (R)-lacosamide and its derivatives has been achieved from commercially available aziridine-(2R)-carboxylate in three simple sequential steps, including regioselective aziridine ring opening, debenzylation followed by acetylation in one pot, and amide formation. The advantage of this protocol is that the starting material and reagents are commercially available and a single purification by recrystallization is required after all the chemical transformations, providing the final drug in >99.9% ee. [ABSTRACT FROM AUTHOR]

Styrenes reacted with sulfonamide in the presence of potassium carbonate and iodine in CHCl3 under visible light irradiation to produce the corresponding aziridines in moderate to good yields. A reaction mechanism to explain the formation of aziridines is also proposed. [ABSTRACT FROM AUTHOR]

This account describes the endeavors made by our group concerning the synthesis of aziridines and azetidin(on)es and their use as novel building blocks for the preparation of nitrogen-containing organofluorine compounds. The majority of contributions, covered in the first part, comprises the study of fluorinated small-ring substrates, focusing on both their synthesis and their synthetic applicability for further transformations. These investigations revealed a pronounced effect of fluorine on the overall reactivity of small-ring azaheterocycles, often resulting in a different behavior compared with that of their nonfluorinated counterparts. In the second part, contributions are covered dealing with the transformation of nonfluorinated small rings into fluorinated target molecules upon treatment with fluorinated reagents. 1 Introduction 2 Synthesis and Reactivity of Fluorine-Containing Aziridines and Azetidines 2.1 Aziridines 2.2 Azetidines 3 Synthesis of Fluorine-Containing Nitrogen Compounds Starting from Nonfluorinated Aziridines and Azetidines 3.1 Aziridines 3.2 Azetidines 4 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

A modular approach to the synthesis of sensors is described. In this approach a central dye scaffold, prepared from the SNAr reaction between a halo-substituted azo-dye and a disubstituted phenol, was decorated with a representative carbohydrate or macrocycle using Sharpless click chemistry. Regiochemical issues in the click reaction are also addressed. [ABSTRACT FROM AUTHOR]

trans-NH-Aziridines were prepared from aliphatic α,β-unsaturated ketones using a tertiary amine promoted reaction via in situ generated N,N-ylides. Through use of modified conditions the reaction proved to be applicable for the diastereoselective aziridination of a range of enolisable aliphatic α,β-unsaturated ketones of varying substitution patterns. [ABSTRACT FROM AUTHOR]

A simple protocol for the synthesis of oxazolidines from aziridines and allylic alcohols is reported. The solid-supported sulfonic acid catalyst can be easily removed after the reaction by a simple filtration leading to the oxazolidine reaction products in good to excellent yields. [ABSTRACT FROM AUTHOR]

A novel procedure for the direct synthesis of 2,5-diaryloxazoles starting from N-H ketoaziridines is described. The method proceeds via the in situ formation of N-bromoketoaziridines in the presence of N-bromosuccinimide followed by the generation of intermediate azomethine ylides. A plausible mechanism for this transformation is proposed. [ABSTRACT FROM AUTHOR]

The effect of the halogen on the rate of sodium amide induced cyclization of 2-haloprop-2-enylamines to methyleneaziridines is studied. Using DFT calculations and competition experiments, it is shown to proceed faster using iodide-based substrates. A practical route to 1-aryl-2-methyleneaziridines is devised based on these observations and their further rearrangement to cyclopropanimines explored. [ABSTRACT FROM AUTHOR]

A new, convenient approach for the reductive ring opening of N-H ketoaziridines is described. Treatment of N-H ketoaziridines with di-tert-butyl dicarbonate [(Boc)2O] in the presence of sodium iodide and nickel(II) chloride results in the corresponding tert-butyl 1,3-diaryl- 3-oxopropylcarbamates by a regiocontrolled reaction. The structure of the regioisomeric product was confirmed by X-ray crystal structure analysis. [ABSTRACT FROM AUTHOR]

The first zinc chloride catalyzed ring opening of N-arylsulfonyl aziridines by thioamides is described. Various thioamides were reacted with N-arylsulfonyl aziridines in the presence of a catalytic amount of dry zinc chloride to provide the corresponding Narylsulfonyl amidine derivatives with good to excellent yields. [ABSTRACT FROM AUTHOR]

This is a personal account on how our research group has exploited trivalent boron-containing organic compounds to create new synthetic methods using small-ring heterocycles. A variety of new regioselective ring-opening reactions (including phenolysis and arylation) that exhibit unusual syn-stereoselectivities can be achieved by making use of the Lewis acidity of boron in aryloxyboranes. On the other hand, the use of the nucleophilic character of diboron derivatives permits regio- and stereocontrolled formation of new C-B bonds. An up-to-date critical coverage of recent relevant literature in the field is also provided. 1 Introduction 2 Ring-Opening Reactions with Triaryloxyboranes 2.1 Carbon-Oxygen Bond Formation with Epoxides, Aziridines, Oxetanes, and Azetidines 2.2 Carbon-Carbon Bond Formation: Stereoselective Arylations of Epoxides and Aziridines 3 Ring Opening with Diboron Compounds 3.1 Metal-Catalyzed and Metal-Free Borylations of Allylic Epoxides and Aziridines 4 Conclusions. [ABSTRACT FROM AUTHOR]

A formal [3+2] cycloaddition between aziridines and alkenes to give the corresponding pyrrolidines was successfully carried out in the presence of a cationic manganese porphyrin catalyst. The use of the porphyrin catalyst allowed, for the first time, styrene derivatives to react with aziridines. [ABSTRACT FROM AUTHOR]

An efficient and stereoselective synthesis of (+)-polyoxamic acid was developed. The route starts with the commercially available 1-(R)-a-methylbenzylaziridine-2-methanol, a substance that has not been used previously as a starting material for the preparation of this target. The route also features the use of a stereocontrolled Sharpless asymmetric dihydroxylation reaction, promoted by AD-mix-a, which is followed by a regioselective aziridine ringopening process, to generate the basic skeleton of target natural product. Subsequent oxidation and global deprotection produces (+)-polyoxamic acid. [ABSTRACT FROM AUTHOR]

Polystyrene-supported 1,5,7-triazabicyclo[4.4.0]dec-5-ene (PS-TBD) catalyzes the ring opening of N-tosylaziridines with trimethylsilyl cyanide, trimethylsilyl azide, or trimethylsilyl halides to give the corresponding products in high yields. PS-TBD can be easily recovered and reused without significant loss of catalytic activity. [ABSTRACT FROM AUTHOR]

Aminimines derived in situ from a number of enantiomerically pure binaphthalene-based tertiary amines have been used for the asymmetric aziridination of chalcone, providing N-unprotected aziridines with ee values of up to 43%. A chiral hydrazinium salt has been isolated for the first time and shown to provide similar yield and enantioselectivity to the in situ process in reaction with chalcone. [ABSTRACT FROM AUTHOR]

The chemistry and synthetic utility of α-lithiated haloalkyloxazolines, oxazolinyl epoxides, and aziridines are highlighted in this account. These lithiated species, which are easily generated, can be captured by electrophiles to give more functionalized derivatives. Spectroscopic and computational studies have proved useful, not only in relation to understanding the chemistry of lithiated species in general, but also in the elucidation of the mechanisms of their lithiation and the stereochemistry of their reactions. The combination of bench experiments with spectroscopic investigations and density functional theory calculations has contributed enormously to increasing the synthetic potential of the lithiated oxazolines that are described in this account. [ABSTRACT FROM AUTHOR]

This account summarizes the Njardarson group ring expansion journey from early vinyl oxirane explorations to the latest vinyl oxetane ring expansion discoveries. The evolution of the program and incredible success of Cu(hfacac)2 as catalyst is detailed. Application of these new ring expansion reactions to natural product, pharmaceutical and commodity chemical targets is discussed as well as our intriguing mechanistic journey and interesting entry into the world of chiral counterion catalysis. [ABSTRACT FROM AUTHOR]

A novel and efficient aminoacetylation of aziridines is reported. Herein, 2-phenyl-1,3-oxazolan-5-one with tosylaziridines affords 3-(N-substituted)aminopyrrolidin-2-ones via regioselective terminal aziridine opening-aminoacetylative cyclization cascades. The reaction is performed using [bmim]OH/molecular iodine as a new catalyst system where ionic liquid [bmim]OH also works as reaction media and proceeds via an isolable intermediate. After isolation of the product, the ionic liquid, [bmim]OH can be easily recycled for further use without any loss of efficiency. No byproduct formation, operational simplicity, ambient temperature, high yield, and excellent diastereoselectivity are salient features of the present synthetic protocol. [ABSTRACT FROM AUTHOR]

A short and efficient synthesis of oxindole-appended allyl amines and 3-vinylaziridine-2-oxindoles have been accomplished in good yield via InCl3/ArSH-mediated ring opening of 3- vinylaziridine-2-oxindoles and sulfur ylide aziridination, respectively. The sulfur ylide was generated in situ from the bromo isomerized Morita-Baylis-Hillman adduct of isatin with N-tosyl imines and tetrahydrothiophene under basic conditions. [ABSTRACT FROM AUTHOR]

Alkenyl aziridines can be successfully arylated in a three-component coupling triggered by in situ generated benzyne with a simple copper catalyst (CuI-PPh3), without the need of any palladium salts. The corresponding allylic amines can be obtained with good to high regioselectivity in mild reaction conditions with a variety of cyclic and acyclic alkenyl aziridines. A new domino reaction with ethyl propiolate to give tetrahydrophenanthridine was also found. [ABSTRACT FROM AUTHOR]

The regioselectivity and stereoselectivity were examined of the addition reactions of O-, C-, N- and S-nucleophiles to D-allaland D-galactal-derived N-mesylaziridines. The ratio of 1,4-regioselectivity (exclusive syn-1,4-addition) to 1,2-regioselectivity (exclusive anti-1,2-addition) was strictly and directly dependent on the ability of the nucleophile to coordinate with the nitrogen atom of the aziridine. [ABSTRACT FROM AUTHOR]

Dimeric α-aziridine aldehydes have been used as the aldehyde component in Ugi and Passerini reactions. The highly reactive mixed anhydride intermediate is subject to nucleophilic attack by the aziridine, leading to 'homo-Ugi' β-acylaziridinyl-α-aminoamides. The products can be readily transformed into substituted lactones. [ABSTRACT FROM AUTHOR]

(1S)-N,N-Dibenzyl-1-[(4R)-2-(4-methoxyphenyl)-1,3- dioxolan-4-yl]ethanamine is obtained in five steps from an abromo- a¢-(R)-sulfinyl ketone and is used as a common intermediate for the synthesis of the p-methoxybenzyl-protected primary and secondary alcohols, (2R,3S)-3-(dibenzylamino)-2-[(4-methoxybenzyl) oxy]butan-1-ol and (2R,3S)-3-(benzylamino)-1-[(4-methoxybenzyl) oxy]butan-2-ol, respectively. These alcohols are further exploited as precursors for the synthesis of a fully protected syn-3- amino-2-hydroxybutanoic acid and an N-benzyl 2-hydroxymethylaziridine. [ABSTRACT FROM AUTHOR]

A grinding-induced, atom-economic, rapid, efficient, one-pot protocol was developed for the synthesis of pharmaceutically relevant benzo-1,4-diazepin-5-ones in excellent yields (72-91%) and high regioselectivities. The method involves a ring-opening--ring-closure cascade of aziridines with anthranilic acids by grinding the neat reactants at room temperature in the presence of lithium bromide as a mild catalyst. Among the advantages of this protocol are its economic viability, the ability to recycle the catalyst, and the formation of water as the only byproduct. [ABSTRACT FROM AUTHOR]

As part of an antibacterial drug discovery project, we were interested in preparing bioisosteric replacement analogues of 4,5-disubstituted oxazolidinones. One such isosteric replacement is the imidazolidinone ring system. Here, we report the development of a general synthesis of 1,4-disubstituted imidazolidinones that takes advantage of the base-catalyzed rearrangement of aminomethyl- substituted oxazolidinones. [ABSTRACT FROM AUTHOR]

Synthesis of a range of functionalised azabicycles from simple linear keto dienoates has been achieved using a tandem enamine formation/Michael addition/aza-Michael addition reaction. [ABSTRACT FROM AUTHOR]