Rhodium(I)‐Catalyzed Intermolecular Aza‐[4+3] Cycloaddition of Vinyl Aziridines and Dienes: Atom‐Economical Synthesis of Enantiomerically Enriched Functionalized Azepines

Abstract

Anew synthetic application of vinyl aziridines as Ncontaining three-atom components in ar hodium-catalyzed [4+ +3] cycloaddition reaction is described. The reaction proceeds well with various silyl dienol ethers and vinyl aziridines,a nd enables the efficient synthesis of highly functionalizeda zepines in an enantioselective manner with net inversion of absolute configuration. The salient features of the transformation include the use of readily available substrates,h igh selectivity,a nd mild reaction conditions,a s well as the versatile functionalization of the products. Chiral azepines,aclass of seven-membered Nheterocycles, Scheme 1. Representative biologically active azepines. Bn = benzyl, Cbz = carboxybenzyl. Scheme 2. [4+ +3] cycloaddition for the synthesis of azepines. Bz = benzoyl, EWG = electron-withdrawinggroup. Angewandte Chemie Communications 1352 www.angewandte.org Thea uthors declare no conflict of interest.

Construction of Oxo-Bridged Diazocines via Rhodium-Catalyzed (4+3) Cycloaddition of Carbonyl Ylides with Azoalkenes

“…Intermolecular (4+3) cycloaddition reactions constitute an atom-economical and step-economical strategy, 5 enabling the convergent synthesis of substituted seven-membered rings from readily accessed substrates. 6 Carbonyl ylides are highly reactive 1,3-dipoles, which could be readily generated through the trap of the metal carbenoid 7 by a carbonyl moiety. The (3+2) cycloaddition of carbonyl ylides formed from diazo compounds mediated by rhodium(II) has been widely applied to synthesize oxacyclic systems.…”