Oxygen ligation in the nickel–mediated [2 + 2 + 2] co-cyclisation of a hepta-1,6-diyne and alkynol derivatives

Abstract

The variation of the yields of the nickel-mediated [2 + 2 + 2] co-cyclisation of a hepta-1,6-diyne with alkynols and alkynol ethers in a regular fashion dependent on the position and steric environment of the oxygen atom is strongly indicative that this atom ligates with the metal during the reaction.