Solid-phase, multicomponent reactions of methyleneaziridines: synthesis of 1,3-disubstituted propanones

Solvent-Controlled Regioselective Reaction of 2-Methyleneaziridines with Acrylic/Propargylic Acids: Synthesis of Carboxylate Aziridine/Acetone Esters

Herein, we report a convenient solvent-controlled regioselective esterification to access two types of carboxylate esters without any additive or non-green activation strategy. In this transformation, 2-methyleneaziridines served as an ester reagent, providing two alternative electrophilic carbon centers. Notably, this protocol is suitable for some structure-complicated clinical molecules with a carboxylic acid group, presenting remarkable application potential.

Bromine radical as a visible-light-mediated polarity-reversal catalyst

Polarity-reversal catalysts enable otherwise sluggish or completely ineffective reactions which are characterized by unfavorable polar effects between radicals and substrates. We herein disclose that when irradiated by visible light, bromine can behave as a polarity-reversal catalyst. Hydroacylation of vinyl arenes, a three-component cascade transformation and deuteration of aldehydes were each achieved in a metal-free manner without initiators by using inexpensive N-bromosuccinimide as the precatalyst. Light is essential to generate and maintain the active bromine radical during the reaction process. Another key to success is that HBr can behave as an effective hydrogen donor to turn over the catalytic cycles.

•

Using bromine as a polarity-reversal catalyst to generate acyl radicals

•

Additive- and metal-free, atom- and step-economic, and operationally simple process

•

Using constant light-irradiation to induce and maintain bromine radicals

•

Access carbonyl compounds and deuterated aldehydes with wide substrate scope

Synthesis and applications of methyleneaziridines

Methyleneaziridines (MAs) are a special subset of aziridines featuring an exocyclic C–C double bond on the three-membered ring. They have found great potential in organic synthesis. In this review, the structural characterization of MAs, synthetic methods, chemical transformations and mechanisms, especially the advances achieved over the past decade are comprehensively summarized.

This review surveys the structural characterization, synthetic methods, chemical transformations and mechanisms of methyleneaziridines, especially the advances achieved over the past decade.

Stereocontrolled lithiation/trapping of chiral 2-alkylideneaziridines: investigation into the role of the aziridine nitrogen stereodynamics

The origin of the stereoselectivity in the lithiation/trapping of 2-alkylideneaziridines bearing a chiral group as the nitrogen substituent was investigated.

A simple and straightforward approach toward selective C=C bond reduction by hydrazine

A simple and straightforward method for reducing the C=C double bond with hydrazine is described. A number of representative C=C bonds in various steric and electronic environments were examined. Substituted alkenes can be selectively reduced in EtOH in the presence of hydrazine to give the corresponding products in up to 100% yields.

Reactivity of N-(omega-haloalkyl)-beta-lactams with regard to lithium aluminium hydride: novel synthesis of 1-(1-aryl-3-hydroxypropyl)aziridines and 3-aryl-3-(N-propylamino)propan-1-ols

The reactivity of 4-aryl-1-(2-chloroethyl)azetidin-2-ones and 4-aryl-1-(3-bromopropyl)azetidin-2-ones with regard to lithium aluminium hydride has been evaluated for the first time. 4-Aryl-1-(2-chloroethyl)azetidin-2-ones were transformed into novel 1-(1-aryl-3-hydroxypropyl)aziridines through an unprecedented conversion of beta-lactams into 2,3-unsubstituted aziridine derivatives. Unexpectedly, 4-aryl-1-(3-bromopropyl)azetidin-2-ones underwent dehalogenation towards 3-aryl-3-(N-propylamino)propan-1-ols upon treatment with LiAlH(4). 1-(1-Aryl-3-hydroxypropyl)aziridines were further elaborated by means of ring opening reactions using benzyl bromide in acetonitrile towards 3-aryl-3-[N-benzyl-N-(2-bromoethyl)amino]propan-1-ols and using aluminium(iii) chloride in diethyl ether, affording 3-aryl-3-[N-(2-chloroethyl)amino]propan-1-ols.

Rapid generation of molecular complexity using "hybrid" multi-component reactions (MCRs): application to the synthesis of alpha-amino nitriles and 1,2-diamines

Methyleneaziridines can be converted into a wide range of 1,2-diamines and 2-cyanopiperidines in a single operation with the formation of three intermolecular carbon-carbon bonds using a "hybrid" MCR.