Double dehydration of a diynediol promoted by a single Co2(CO)6 unit; activation of an uncoordinated propargylic centre

Abstract

The acid-catalysed elimination of two molecules of water from a diynediol requires only one of the alkyne functionalities to be coordinated to a dicobalt hexacarbonyl fragment; it is proposed that the reaction proceeds via an unprecedented type of intermediate in which a carbocationic centre is stabilised by a non-adjacent dicobalt hexacarbonyl moiety.