Rhodium(II)-Catalyzed Cyclization of 2-Alkynyl 2-Diazo-3-oxobutanoates as a Method for Synthesizing Substituted Furans

Article abstract of DOI:10.1021/jo00053a009

A series of 2-alkynyl 2-diazo-3-oxobutanoates, when treated with a catalytic quantity of rhodium(II) acetate, were found to produce furo<3,4-c>furans in good yield.The reaction proceeds by addition of a rhodium-stabilized carbenoid onto the acetylenic ?-b