A new type of base-induced isomerisation of 1,3-enynes; the reversal of an enyne system

A new type of base-catalysed isomerisation of conjugated enynes leads to the reversed enyne systems. The preparative conversion of 1-(dialkylamino)-3-buten-1-ynes (1) into 1-(dialkylamino)-1-buten-3-ynes (2) is presented.