Regioselective synthesis of functionalized furans by cyclization of 1,3-bis-silyl enol ethers with 1-chloro-2,2-dimethoxyethane

Cyclization of 1,3-bis-silyl enol ethers with 1-chloro-2,2-dimethoxyethane allowed an efficient, regio- and diastereo-selective synthesis of a variety of 2-alkylidene-4-methoxytetrahydrofurans. The TFA-mediated elimination of methanol resulted in the formation of functionalized furans. Similarly, 2,3,3a,4,5,6-hexahydro-2,3-benzofurans were prepared and transformed into 4,5,6,7-tetrahydro-2,3-benzofurans by treatment with TFA. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)