The regiospecific C-4 lithiation of 2-(tert-butyldimethylsilyl)-3-furoic acid
Abstract
2-(tert-Butyldimethylsilyl)-3-furoic acid 7 was regiospecifically lithiated at the C-4 position when treated with 2.5 equiv. of butyllithium (at –20 °C) in either tetrahydrofuran or 1,2-dimethoxyethane; trapping of the dianion with a variety of electrophiles provided 2,3,4-trisubstituted furans in good to excellent yield.