Search

A synthetic method to prepare o-phenolic esters efficiently by gold(I)-catalyzed benzannulation of 5-hydroxy-3-oxoalk-6-ynoate esters under mild conditions that did not require the exclusion of air or moisture is described.

An efficient AgOTf-catalyzed (TfO = trifluoromethanesulfonate) cyclopropyl carbinol rearrangement for the synthesis of benzo[ b]oxepines and 2 H-chromenes is reported by starting from 2-[cyclopropyl(hydroxy)methyl]phenols. The reactions proved to be general in scope and furnished a range of the corresponding functionalized oxygen heterocycles. The formation of the benzo-fused six-membered adduct is proposed to result from the ring-contraction of the benzo[ b]oxepine derivative. Control of the product selectivity is achievable by fine-tuning the reaction time. The catalytic synergy between the silver(I) cation and the triflate anion was essential for optimal product yields. [ABSTRACT FROM AUTHOR]

A wide range of functionalized oxygen heterocycles are obtained by a general method starting from 2-[cyclopropyl(hydroxy)methyl]phenols. [ABSTRACT FROM AUTHOR]