An unusual reaction of propargylamines with CH2I2 and Et3Al

Abstract

N {2 [(1 R Cyclopropyl)methyl]prop 2 enyl} N,N dimethylamines were prepared in 80-90% yields by the reaction (5 h, 23-25°C) of propargylamines R-C≡C-CH 2 NMe 2 (where R = alkyl, Ph) with a system of reactants CH 2 I 2 -Et 3 Al taken in the molar ratio [propargylamine] : [Et 3 Al] : [CH 2 I 2 ] = 1 : 6 : 6. In the case of phenyl substituted propargyl amine, N ({1 [(1 phenylcyclopropyl)methyl]cyclopropyl}methyl) N,N dimethylamine is selectively formed in 76% yield upon the elongation of the reaction time to 4 days.

Aluminum Carbenoid R₂AlCH₂I – a New Cyclopropanation Agent for the Transformation of Unsaturated Amines into Cyclopropyl Amines

“…Over the last few years the authors have developed a new approach to the synthesis of cyclopropane compounds based on the reaction of substituted alkynes and allenes with aluminum carbenoids [1,2]. Substituted propargyl alcohol and amines have been successfully involved in the reaction [3,4]. At the same time, only a few examples for the cyclopropanation of functionally-substituted alkenes…”