The Lewis acid-catalyzed reactions of olefins with chloromethoxymethane (CM) or dimethoxymethane (DM) and aliphatic or aromatic nitriles afforded the 1: 1: 1 adducts and/or their hydrolysis products in various yields, together with the 1: 1 olefin–CM (or DM) adducts. AlCl 3, FeCl 3, ZnCl 2, and SnCl 4 were effective catalysts for the reaction with CM, whereas BF 3 and SnCl 4 were effective for that with DM. In the case of cyclohexene, the addition ...