ASYMMETRIC-SYNTHESIS OF BUTENOLIDE AND BUTYROLACTONE DERIVATIVES

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