Electrophile-Mediated Reactions of Functionalized Propargylic Substrates

Metal-free halogen, chalcogen, or oxocarbenium ion mediated yne-carbonyl or yne-thioxo transformations of a range of N- and O-propargylic compounds have been studied. This investigation has led to the development of a mild, economic, and effective method for the synthesis of functionalized 4H-1,3-oxazines, 4H-1,3-thiazines, 4,5-dihydrothiazoles, and alpha-substituted enones. The structure of the propargylic substrate and the nature of electrophile influence both the outcome and regioselectivity of processes.