1,4-Electrocyclic reactions in the chemistry of four-membered carbocyclic and heterocyclic compounds (review)

The electrocyclic reactions of four-atom compounds are examined. The diversity of the mechanisms of cyclizations and the synthetic utilization of 1,4-electrocyclizations of derivatives and heteroanalogs of butadiene is demonstrated. Special attention was directed to the transformation of the heterocyclic compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1155–1173, September, 1993.