A novel Darzens-type condensation using .alpha.-chloro ketimines

The Favorskii Rearrangement: Synthetic Applications

“…Butenamides 67 (Scheme 22) have been prepared by a base-induced rearrangement of , -epoxy imines 64 [37]. Deprotonation of the latter with LDA followed by ringclosing by cleavage of one carbon-oxygen bond of the epoxide generated alkoxides 6 5 , which were then transformed into the bicyclic intermediates 66 by addition of the alkoxide to the imine.…”

Highly Regioselective Transformation of Alkenyl Bromides into α-Bromoaziridines and α-Bromohydrazones

“…α-Halogenated imines and hydrazones have been used for the preparation of diimines, epoxyimines, cyclopropylamines, pyrrolidines, and pyrroles. 1a, However, the efficient synthesis of α-halogenated imines and hydrazones is an underdeveloped area in comparison with α-halogenated aldehydes and ketones . This is due to the difficulties encountered during the preparation of these intermediates.…”

A Convenient Synthesis of 3,3-Dichloroazetidines, a New Class of Azetidines

“…Surprisingly, when the condensation was performed with aliphatic aldehydes, such as 2-ethylbutanal, instead of aromatic aldehydes 9 , a mixture of cis - and trans -2-chloro-2-imidoyloxiranes 10 was obtained via a Darzens-type reaction (Scheme ). A novel Darzens-type condensation of α-monochlorinated ketimines with carbonyl compounds producing α,β-epoxy ketimines has already been reported by us . It has also been described that the anion of 2-(dichloromethyl)-4,4-dimethyl-2-oxazoline reacts with carbonyl compounds to give 2,2-dichloro-3-hydroxy- or 2-chloro-2,3-epoxy-2-oxazolines depending on the reaction conditions …”