Protecting group-free use of alcohols as carbon electrophiles in atom efficient aluminium triflate-catalysed dehydrative nucleophilic displacement reactions

Benzylic and allylic alcohols are rendered electrophilic without chemical modification by the use of aluminium triflate as catalyst. The reaction succeeds with alcohol, thiol, carbon and nitrogen nucleophiles. When phenols are employed as nucleophiles, C-alkylation ensues. An advanced application of the method is demonstrated in the synthesis of 2H-chromenes and their N and S analogues.