Asymmetric Mukaiyama aldol reaction of silyl enol ethers with aldehydes using a polymer-supported chiral Lewis acid catalyst
作者:Shinichi Itsuno、Shinnosuke Arima、Naoki Haraguchi
DOI:10.1016/j.tet.2005.07.110
日期:2005.12
α-amino acid monomer (5) derived from (S)-tryptophan was copolymerized with styrene and divinylbenzene under radical polymerization conditions to give a polymer-supported N-sulfonyl-(S)-tryptophan (6). Treatment of the polymer-supported chiral ligand with 3,5-bis(trifluoromethyl)phenyl boron dichloride afforded a polymeric Lewis acid catalyst (16) effective for asymmetric Mukaiyama aldol reaction of silyl
在自由基聚合条件下,将衍生自(S)-色氨酸的手性N-磺酰化α-氨基酸单体(5)与苯乙烯和二乙烯基苯共聚,得到聚合物负载的N-磺酰基-(S)-色氨酸(6)。用3,5-双(三氟甲基)苯基二氯化硼处理聚合物负载的手性配体,得到了一种聚合的路易斯酸催化剂(16),其对于甲硅烷基烯醇醚和醛的不对称Mukaiyama aldol反应是有效的。在聚合手性路易斯酸的存在下,使各种醛与甲硅烷基烯醇醚反应,以高收率和高对映体选择性得到相应的羟醛加合物。