Dispiroketals in synthesis (part 9): Resolution of 1,2-diols using a C2-symmetric diphenyltetrahydrobipyran

Article abstract of DOI:10.1016/0957-4166(94)80016-2

A series of 1,2-diols were resolved by the enantioselective formation of the thermodynamically most stable dispiroketal using (2R,2'R) and (2S,2'S) 2,2'-diphenyl-3,3',4,4'-tetrahydro-6,6'-bi-2H-pyran 2 and 3. Deprotection was achieved using a metal ammonia reduction to liberate the resolved diols.