Stereoselective pinacol coupling of planar chiral (benzaldehyde)Cr(CO)3, (benzaldimine)Cr(CO)3, ferrocenecarboxaldehyde and (dienal)Fe(CO)3 complexes with samarium diiodide
作者:Nobukazu Taniguchi、Motokazu Uemura
DOI:10.1016/s0040-4020(98)00778-9
日期:1998.10
intermolecular pinacol coupling of the planar chiral tricarbonylchromium complexes of o-substituted benzaldehydes or benzaldimines with samarium(II) diiodide in THF produces exclusively threo 1,2-diols or 1,2-diamines in an optically pure form, while the corresponding racemico-substituted benzaldehyde or benzaldimine chromium complexes give a mixture of threo and erythro pinacol coupling products in a various
分子间频哪醇的平面手性tricarbonylchromium的络合物耦合ø -取代的苯甲醛或与钐benzaldimines(II)二碘化物在THF只产生苏1,2-二醇或以光学纯形式的1,2-二胺,而相应的外消旋Ò取代的苯甲醛或苯甲二胺铬配合物可根据邻位取代基的性质,以不同的比例生成苏式和赤式频哪醇偶联产物的混合物。同样,平面手性2-取代的二茂铁甲醛和(二元)Fe(CO)3产生具有高立体选择性的相应的1,2-二醇。所生成的过渡金属络合的羰自由基中间体是构型上用限制到一个关于C旋转稳定α C本位键。