Asymmetric synthesis of (+)- and (−)-dihydropinidines: diastereoselective addition to chiral imine or 1,3-oxazolidine derived from (R)-phenylglycinol as a single starting material with organometallic reagents
作者:Takayasu Yamauchi、Hideki Fujikura、Kimio Higashiyama、Hiroshi Takahashi、Shigeru Ohmiya
DOI:10.1039/a905061b
日期:——
construction of both enantiomers of the natural products by using a single chiral source, (R)-phenylglycinol. Both routes were carried out by similar processes, except for either the presence of an imine or 1,3-oxazolidine intermediate. Excellent diastereoselectivity was observed in the reaction of chiral imines and 1,3-oxazolidines with organometallic reagents, to give the chiral amines in high chemical
(+)-和(-)-二氢吡啶类对映体对的不对称合成已经完成。我们的策略是基于天然产物的两种对映体的对映结构通过使用具有单一手性源,(ř)-苯基甘氨醇。除存在亚胺或1,3-恶唑烷中间体外,两种途径均通过相似的方法进行。在手性亚胺和1,3-恶唑烷与有机金属试剂的反应中观察到极好的非对映选择性,从而以高化学产率得到手性胺。两种胺的绝对构型是通过将它们各自转化为二氢吡啶而确定的。(+)-和(-)-二氢吡啶吡啶哌啶生物碱的不对称合成分别通过四个步骤完成,总产率分别为6和11,分别为46%和59%。