Regioselective Cu-Catalyzed Hydroboration of 1,3-Disubstituted-1,3-Dienes: Functionalization of Conjugated Dienes Readily Accessible through Ene–Yne Metathesis
Regioselective Cu-Catalyzed Hydroboration of 1,3-Disubstituted-1,3-Dienes: Functionalization of Conjugated Dienes Readily Accessible through Ene–Yne Metathesis
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DOI：
10.1021/acscatal.2c01190
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发表时间：
2022-05
期刊：
影响因子：
12.9
通讯作者：
Ruoshui Xu;Laurence N Rohde;S. Diver
中科院分区：
文献类型：
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作者：
Ruoshui Xu;Laurence N Rohde;S. Diver
报道了一种区域选择性的铜催化的1，3-二取代-1，3-二烯的甲醛硼氢化反应。通过催化烯-炔复分解反应产生的高度取代的1，3-二烯提供了区域选择性硼氢化反应的底物，其具有方便地从1-烯烃和末端炔引入的可变取代基。对于非手性反应，使用双膦1，2-双（二苯基膦基）苯（dppbz）作为配体。在对映选择性反应中，以EtDuPhos为双膦配体，在大多数情况下获得了良好的对映选择性。对照研究表明，1，3-二烯的立体异构纯度和Cu（I）源是导致最高区域选择性的关键变量。原位NMR实验和氘淬灭证实了烯丙基铜中间体的存在，其不与其他1，3-二烯交换。区域选择性的一个建议的模型是基于添加Cu-B的1，3-二烯，其中在3，4-加成的空间效应比那些在有利的1，2-加成模式更严重。将产物进一步官能化并用于双催化交叉偶联反应。
A regioselective Cu-catalyzed formal hydroboration of 1,3-disubstituted-1,3-dienes is reported. Highly substituted 1,3-dienes produced through catalytic ene–yne metathesis provided substrates for the regioselective hydroboration with variable substituents conveniently introduced from a 1-alkene and a terminal alkyne. For the achiral reaction, the diphosphine 1,2-bis(diphenylphosphino)benzene (dppbz) was used as the ligand. For the enantioselective reaction, EtDuPhos was used as the diphosphine ligand, and good enantioselectivites were obtained in most cases. Control studies showed that the stereoisomeric purity of the 1,3-diene and the Cu(I) source were key variables that led to the highest regioselectivity. In situ NMR experiments and deuterium quenching confirmed the presence of an allyl copper intermediate, which did not exchange with other 1,3-dienes. A proposed model for the regioselectivity is based on the addition of Cu-B to the 1,3-diene where steric effects in the 3,4-addition are more severe than those in the favored 1,2-addition mode. The products were further functionalized and were employed in a dual-catalytic cross-coupling reaction.