ASYMMETRIC-SYNTHESIS OF BUTENOLIDE AND BUTYROLACTONE DERIVATIVES

2-Trimethylsiloxyfuran and 4-methoxy-2-trimethylsiloxyfuran, which are readily prepared from butenolide and methyl tetronate respectively, h ave been reacted with a series of homochiral ortho-esters and oxazolid ine derivatives in the presence of Lewis acids to afford homochiral 2( 5H)-furanone derivatives. The structures of these products have been d etermined using nmr spectroscopy and, where possible, by X-ray analysi s. Preliminary experiments have been carried out involving conjugate a ddition to these unsaturated lactones, demonstrating their potential a s substrates for natural product synthesis.