Preparation and Diels-Alder Reactivity of Several New Chalcogen-Halogen Substituted Butadienes

Article abstract of DOI:10.1021/jo00190a021

Addition of halogens and pseudohalogens across one ?-bond of 1,4-dichlorobut-2-yne, followed by a 1,4-elimination, is an efficient synthesis of several new polysubstituted butadienes.If the product dienes have a sulfur or selenium substituent they are quite reactive, undergoing cycloaddition with the moderately reactive dienophile methyl vinyl ketone at 20 deg C in the presence of boron trifluoride etherate.The regiochemistry of the cycloadditions was elucidated, and the limitations of the methodology are discussed.