Utilization of various hydride-ion acceptors in the reaction of acetals with ketones
The ability of a number of compounds (acetyl perchlorate, iodine, phosphorus oxychloride, and phosphorus pentachloride) to detach a hydride ion from the meso carbon atom of 1,5-diketones that are formed in the condensation of acetals with ketones and are cyclized to symmetrical pyrylium salts was studied.