New synthesis of N-aryl-2-methyleneazetidines

Abstract

A novel straightforward synthesis of jV-aryl-2-methyleneazetidines has been developed by reaction of TV-aryl /3-chloro ketimines with potassium fert-butoxide.

1-Azaallylic Anions in Heterocyclic Chemistry

“…41 The same Darzens reaction was observed starting from R,R-dichloroketimines. When N-(2,2-dichloro-1-phenylethylidene)isopropylamine (27) was reacted with 2-ethylbutanal, a 1:1 mixture of cis-and trans-2-chloro-2-imidoyloxiranes 28 was obtained (Scheme 11).…”

“…As a proof, using -chlorinated N-arylimines, 2-methoxy-1-phenylazetidines 35 (R ) Ph) could be isolated. 44,45 In this matter, N-benzyl-R-chloroaldimines do not give rise to azetidines as they suffer base-induced 1,4-dehydrochlorination to 2-aza-1,3-dienes. 46,47 Moreover, treating R-chloro-and R-bromoimines with N-bases (triethylamine, DABCO, DBU) in alcohols led, via the corresponding 1-azaallylic anion enamine, to 1-alkoxy-1-aminocyclopropanes, R-alkoxyimines, and rearranged R-aminoacetals in various ratios depending on the reaction conditions.…”

Magnesium iodide promoted defluorinative reactions of 2,2-difluorocyclopropyl aryl ketones with aryl imines: A new, general synthesis of 2-alkylideneazetidines

“…prepared either by methylenation of b-lactams using dimethyltitanocene [8,9], or by cyclization reactions [10][11][12]. 2-Alkylideneazetidine compounds with a conjugated enone structure like those in 6 are even less frequently encountered.…”

Use of 3‐Halo‐1‐azaallylic Anions in Heterocyclic Chemistry

“…The reports include alkylations [3], reactions with aldehydes, and ketones [4]. In one case of fluorinated species, temperature-dependent regioselective alkylations to α-fluoroimines could be achieved [5].…”