Yu Congjun, Zhang Zining, Dong Guangbin
Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States.
Nat Catal. 2024 Apr;7(4):432-440. doi: 10.1038/s41929-024-01120-9. Epub 2024 Mar 11.
Constructive functionalization of unstrained aryl-aryl bonds has been a fundamental challenge in organic synthesis due to the inertness of these bonds. Here we report a split cross-coupling strategy that allows two-fold arylation with diverse aryl iodides through cleaving unstrained aryl-aryl bonds of common 2,2'-biphenols. The reaction is catalyzed by a rhodium complex and promoted by a removable phosphinite directing group and an organic reductant. The combined experimental and computational mechanistic studies reveal a turnover-limiting reductive elimination step that can be accelerated by a Lewis acid co-catalyst. The utility of this coupling method has been illustrated in the modular and simplified syntheses of unsymmetrical 2,6-diarylated phenols and skeletal insertion of phenyl units.
由于未受张力的芳基-芳基键具有惰性，其构建性官能化一直是有机合成中的一项基本挑战。在此，我们报道了一种拆分交叉偶联策略，该策略通过裂解常见的2,2'-联苯酚的未受张力的芳基-芳基键，实现与多种芳基碘化物的双重芳基化反应。该反应由铑配合物催化，并由可去除的亚膦酸酯导向基团和有机还原剂促进。结合实验和计算的机理研究揭示了一个周转限制的还原消除步骤，该步骤可由路易斯酸共催化剂加速。这种偶联方法的实用性已在不对称2,6-二芳基化苯酚的模块化和简化合成以及苯基单元的骨架插入中得到了证明。
