摘要:
Intermolecular [2+2] photocycloaddition reactions between 3-(2-oxo-2H-chromene-3-carbonyl)oxazolidin-2-one with n-propyl vinyl ether and vinyl pivalate were carried out to give [2+2] cycloadducts in excellent yield with perfect regioselectivity. A Lewis acid catalyst (30 mol%) was moderately effective in accelerating the reaction. Furthermore, enantioselective reactions catalyzed by chiral Lewis acid catalysts (30 mol%) were performed to give cycloadducts in excellent yields with up to 13% ee.