Unexpected E-stereoselective reductive A3-coupling reaction of terminal alkynes with aldehydes and amines.

Fan, Wu; Yuan, Weiming; Ma, Shengming · Nat Commun · 2014

basic_science · Level V

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Abstract

The transition-metal catalysed three-component coupling of an alkyne, an aldehyde and an amine has been became a widely used method for preparing propargylic amines. Here, we report an unexpected copper(I)-catalysed E-stereoselective reduction of propargylic amines in situ formed from readily available terminal alkynes, aldehydes and 3-pyrroline or isoindoline via [1,5]-hydride transfer, affording E-allylic amines. Through mechanistic studies, it is believed that the unsaturated cyclic dialkylamine is acting as hydrogen donor.