Chiral phosphine oxide sequentially activates silicon tetrachloride and trichlorosilyl enol ethers to facilitate asymmetric aldol/vinylogous aldol reaction of 4-methoxy-3-penten-2-one and conjugated aldehydes in a highly enantioselective fashion, and the subsequent cyclization produced optically active 2,6-disubstituted 2,3-dihydro-4-pyranones bearing stereogenic centers at a remote position in a single
手性氧化膦顺序地活化
四氯化硅和三
氯甲
硅烷基烯醇醚,以促进
4-甲氧基-3-戊烯-2-酮与共轭醛的不对称醛醇/
乙烯基醛醇反应,以高度对映选择性的方式发生,随后的环化反应产生旋光性2,6一次操作中,β-二取代的2,3-二氢-4-
吡喃酮在较远的位置带有立体异构中心。