A convergent total synthesis of pumiliotoxins A and B via palladium-catalyzed cross-coupling reaction of homoallylic organozinc compounds with vinyl iodides
作者:Chihiro Kibayashi、Sakae Aoyagi
DOI:10.1016/s0022-328x(02)01160-9
日期:2002.7
pumiliotoxin alkaloids has been developed employing a Pd(0)-catalyzed cross-coupling reaction between homoallylic organozincs and vinyl iodides, which led to the asymmetric total synthesis of (+)-pumiliotoxins A (1) and B (2). The (Z)-alkylideneindolizidine, which is a common organic part of the organozinc reagents in this approach, was synthesized with a high degree of stereocontrol upon using HfCl4-mediated
已经开发出一种通用的聚合方法来制备pumiliotoxin生物碱,该方法利用Pd(0)催化的均聚物有机锌与乙烯基碘之间的交叉偶联反应,导致(+)-pumiliotoxins A(1)和B的不对称全合成。(2)。在这种方法中,作为有机锌试剂的常见有机部分的(Z)-亚烷基亚吲哚并咪唑是通过使用HfCl 4介导的将烯丙基硅烷加到(S)-2-乙酰基吡咯烷中而以高度立体控制合成的。(Z)-碘亚烷基亚吲哚并核苷(31如此获得的作为高级通用中间体)被转化为高烯丙基氯化锌衍生物32,使用Pd(PPh 3)4催化剂与(E)-乙烯基碘化物(13)进行高烯丙基-乙烯基交叉偶联,得到1,5 -二烯产物33。随后的脱保护作用提供了(+)-pumiliotoxinA。另一方面,将31转化为均烯丙基叔丁基锌中间体39,该中间体与(E)-乙烯基碘化物(36)交联。 Pd(0)催化剂。所得的1,5-二烯产物40 进行后续的