作者:Ricardo J. Maza、Elliot Davenport、Núria Miralles、Jorge J. Carbó、Elena Fernández
DOI:10.1021/acs.orglett.9b00531
日期:2019.4.5
This work explains the reactivity of diboron reagents with 1,3-dienes in a transition-metal-free context. The sole addition of Na2CO3 (30 mol %) to bis(pinacolato)diboron in MeOH allows the 1,4-hydroboration of cyclic and noncyclic 1,3-dienes. The electronic influence on the substrate guarantees the conjugated 1,4-hydroboration versus 1,2-diboration. DFT calculations show that the distribution of charge
这项工作解释了在无过渡金属的情况下乙硼试剂与1,3-二烯的反应性。将Na 2 CO 3(30mol%)仅添加至在MeOH中的双(频哪醇)二硼中,可以使环状和非环状的1,3-二烯进行1,4-氢硼化。电子对底物的影响保证了共轭的1,4-氢硼化与1,2-二硼化。DFT计算表明,烯丙基阴离子中间体中的电荷分布决定着1,4-氢硼化的选择性,而二烯试剂中有利的反式构型决定了对烯丙基硼酸E酯的偏爱。