Abstract
A variety of 3-(silyloxycarbonyl)furans and -thiophenes undergo 1,4 @C silyl migration to provide the corresponding 2- silylated 3-carboy heterocycles in moderate to good yield when treated with a mixture of lithium diisopropylamide and hexa- methylphosphoric triamide in tetrahydrofuran at -78 C. We recently required 2-(I-butyldimethyl)silyl-3-furoic acid 3 as a starting material for the synthesis of some furan containing natural products. bight1 has reported that 2-substituted 3-furoic acids 2 can be simply prepared by mating 3-furoic acid 1 with two equivalents of LDA (THF, -78°C) followed by a quench with a suitable electrophile (Scheme 1). In our hands, employing t-butyldimethylsilyl chloride as the electrophile, the desired acid 3 was only formed in 5% yield. SCHEME 3
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