Stereoselective hydrostannation: Synthesis and absolute configuration of (−)-menthyl 2,3-diphenyl-3-(trimethylstannyl) propanoates and derivatives
作者:J.C. Podestá、A.B. Chopa、L.C. Koll、S.D. Mandolesi
DOI:10.1016/0022-328x(92)83365-o
日期:1992.8
11–12, respectively, which were isolated and characterized by spectroscopic methods. The reduction of bromo esters 9–12 with lithium aluminium hydride gave (R)-(−)- and (S)-(+)-2,3-diphenyl propanols 13 and 14 of known absolute configuration. Working back from the stereochemistry of 13 and 14 and taking into account the NMR data, the stereochemistry of their precursors was assigned. Full 1H, 13C, and
(-)-薄荷基(E)-2,3-二苯基丙酸酯(1)的自由基加氢锡化反应产生了四种加合物的混合物:两种苏式非对映异构体(约90%)和两种赤式非对映异构体(约10%)。而苏式非对映体2(38%)和3(51.2%)可通过柱色谱法和分步重结晶来分离,赤非对映体4和4'(6.5%和4.3%)不能被分离。2和3的溴代苯乙烯甲酰化在每种情况下均产生两种非对映异构体,即9-10和11-12分别通过光谱法分离和表征。用氢化锂铝还原溴酸酯9-12可获得已知绝对构型的(R)-(-)-和(S)-(+)-2,3-二苯基丙醇13和14。从13和14的立体化学出发,并考虑NMR数据,确定了其前体的立体化学。给出了全部1 H,13 C和119 Sn NMR数据。