Iodo- and Chalcogenoannulation of Morita-Baylis-Hillman Alcohols of Propiolaldehydes: Entry to Functionalized 2-Pyrones.

An efficient intramolecular annulation of Morita-Baylis-Hillman (MBH) alcohols of propiolaldehydes is developed in the presence of ICl or PhSeSePh/PhSSPh-CuCl2. This cyclization offers access to a wide variety of iodinated or chalcogenated 3-(chloromethyl)-2-pyrones in good yields. The chloromethyl group of the obtained 2-pyrones has been easily converted to introduce other handy functionalities, which allowed for further transformations to synthesize diverse 2-pyrone containing molecules.