Synthesis of 2,3-di- and 2,3,4-trisubstituted furans from 1,2-dioxines generated by an enyne-RCM/Diels-Alder reaction sequence

[GRAPHICS] An efficient method for the synthesis of 2,3- and 2,3,4-substituted furans starting from acyclic enynes was developed using an enyne-RCM/Diels-Alder reaction sequence. The reaction conditions for the transformation of 1,2-dioxines having an adjacent 1,2-oxazine ring into furans and the cleavage of N-O bonds are discussed.