Imidazole Transfer from 1,1'-Carbonyldimidazole and 1,1'-(Thiocarbonyl)diimidazole to Alcohols. A New Protocol for the Conversion of Alcohols to Alkylheterocycles.

The transfer of imidazole from 1,1'-carbonyldimidazole (CDI) and 1,1'-(thiocarbonyl)diimidazole in modest to excellent yields under mild conditions was observed with activated alcohols, unactivated alcohols generally providing the expected carbonylimidazole esters. Reasonable mechanisms for the transfer are proposed. 1,1'-Carbonyldi-1,2,4-triazole was found to work as well, providing a new heterocycle in good yield. Chemists should be aware of this reaction when treating benzylic, vinylogous benzylic, and benzhydryl alcohols with CDI-type reagents, expecting elimination of heterocycle rather than incorporation of heterocycle and elimination of CO(2).