Cyclisation of 2-methylbut-3-yn-2-ol. Part II. Cyclisation to cyclo-octatetraene derivatives

Abstract

Cyclisation of 2-methylbut-3-yn-2-ol to a mixture containing mainly 1,2,4,6-, 1,2,4,7-, and 1,3,5,7-tetrakis(1-hydroxy-1-methylethyl)cyclo-octatetraene has been achieved with the following catalyst systems; (a) nickel tetracarbonyl or bis(cyclo-octadiene)nickel(O); (b) sodium borohydride and nickel(II) salt; (c) divalent nickel compounds such as Ni(CN)₂, Ni(acac)₂, and Ni(OEt)₂. Products were identified by their spectra and those of their dehydration derivatives. Tetrameric compounds with nuclear magnetic resonance spectra consistent with a cyclo-octatetraene structure, together with aromatic compounds, have also been obtained from propargyl alcohol.