Rearrangement of 4-alkynylcyclobutenones. A new synthesis of 1, 4-benzoquinones

…, JO Karlsson, ST Perri, R Schwabe, SL Xu…

Index: Foland, Lafayette D.; Karlsson, J. Olle; Perri, Steven T.; Schwabe, Rudolf; Xu, Simon L.; et al. Journal of the American Chemical Society, 1989 , vol. 111, # 3 p. 975 - 989

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Citation Number: 113

Abstract

Abstract: A new convergent synthesis of 1, 4-benzoquinones from 4-alkynyl-4-alkoxy (or hydroxy or trimethylsily1oxy) cyclobutenones is described. The required cyclobutenones are prepared from squaric acid and converted to the quinones upon mild thermolysis. The reaction proceeds via electrocyclic ring opening of the required cyclobutenones to (2- alkynylethenyl) ketenes, which then ring close to unique diradical intermediates. These ...