新奇遠隔不斉誘導反応によるポリアセテート型 およびアセテート─プロピオネート混合型 ポリケチドの合成

Polyacetate-type and acetate-propionate hybrid-type polyketide skeletons have been constructed by the remote asymmetric induction of the vinylogous Mukaiyama aldol reactions using chiral oxazolidinone-attached vinylketene silyl N,O-acetals. In the acetate-propionate hybrid-type reaction, anti- and syn-adducts were selectively afforded using aldehydes and acetals, respectively. Therefore, in conjunction with the previously reported polypropionate-type reaction, all types of polyketide skeletons have been able to be synthesized. In addition to the transition states of the acetate-propionate hybrid-type reactions, difference of the stereo-control systems between the polyacetate-type reaction and the polypropionate-type reaction is discussed. Interestingly, in polyacetate-type and acetate-propionate hybrid-type reactions, the chiral auxiliary controlled the stereoselectivity indirectly. Additionally, (S)-massoialactone (α,β-unsaturated δ-lactone) and tabtoxinine-β-lactam, an inhibitor of glutamate synthetase, were synthesized by the remote asymmetric induction reactions.