THERMALLY INITIATED REACTIONS OF (Z)-EPOXYHEXENYNES A FACILE PREPARATION OF 3,4-ANNULATED FURANS

Article abstract of DOI:10.1016/S0040-4020(01)90602-7

An efficient and general access to 3,4-annulated 2-vinylfurans (type II) is provided by the thermally induced ring transformation of epoxyhexenynes (I).Depending on the substitution pattern the reactions proceed either by heating in solution (5a-h) or under short-time thermolysis conditions (6i, j).The results are consistent with a multistep mechanism involving 1-oxacyclohepta-3,4,6-trienes as central intermediates.