Cobalt-catalyzed regioselective stereoconvergent Markovnikov 1,2-hydrosilylation of conjugated dienes
作者:Hui Leng Sang、Songjie Yu、Shaozhong Ge
DOI:10.1039/c7sc04002d
日期:——
an allylcobalt species generated by the 1,4-hydrometalation of Z-dienes. In addition, a cobalt catalyst that can only catalyze the hydrosilylation of the E-isomer of an (E/Z)-diene was identified, which allows the separation of the (Z)-isomer from an isomeric mixture of (E/Z)-dienes. Furthermore, asymmetric hydrosilylation of (E)-1-aryl-1,3-dienes was studied with Co(acac)2/(R)-difluorphos and good
我们报告了使用从稳定的Co(acac)2和膦配体生成的催化剂的共轭二烯的第一个立体收敛Markovnikov 1,2-氢硅烷化。各种各样的E / Z二烯以立体会聚方式进行了1,2,2-氢化硅烷化反应,以高分离度(E / Z => 99:1)和高区域选择性(b)得到高分离产率的(E)-烯丙基硅烷/ l到> 99:1)。机理研究表明,这种立体收敛源自Z的1,4-加氢金属化生成的烯丙基钴物种的σ–π–σ异构化-dienes。另外,鉴定了只能催化(E / Z)-二烯的E-异构体的氢化硅烷化的钴催化剂,其允许从(E / Z)的异构体混合物中分离(Z)-异构体。-dienes。此外,用Co(acac)2 /(R)-二氟化合物研究了(E)-1-芳基-1,3-二烯的不对称氢化硅烷化反应,并获得了良好的对映选择性(最高90:10)。