Transition-metal-catalyzed oxidative cross-dehydrogenative coupling(CDC)reactions represent an attractive strategy for the direct construction of C-C and C-X(X=heteroatom)bonds,owing to their inherent atom and step ec...Transition-metal-catalyzed oxidative cross-dehydrogenative coupling(CDC)reactions represent an attractive strategy for the direct construction of C-C and C-X(X=heteroatom)bonds,owing to their inherent atom and step economy.This strategy has been recently extended to the B-H/C-H cross-dehydrogenative coupling of carboranes with arenes.However,such transformations typically either rely on the assistance of directing groups or are restricted to intramolecular processes.Herein,we report a palladium-catalyzed direct cross-dehydrogenative coupling between the B-H bond of carboranes and the C-H bond of(hetero)arenes,which affords B(9)-arylated products of o/m-carboranes in good to excellent yields with a broad substrate scope.Notably,this methodology is not limited to simple benzene rings but also delivers high yields with polycyclic aromatic hydrocarbons,five-membered heterocycles,and benzo-fused five-membered heterocycles.Control experiments reveal that B-H activation occurs preferentially over C-H activation.The high reactivity of carboranes toward Pd(II)and their steric hindrance are the keys to this successful transformation,suppressing the formation of(hetero)arene and carborane homo-coupling products,respectively.展开更多
基金supported by National Natural Science Foundation of China(Grant No.22271256)Natural Science Foundation of Henan Province(232300421088).
文摘Transition-metal-catalyzed oxidative cross-dehydrogenative coupling(CDC)reactions represent an attractive strategy for the direct construction of C-C and C-X(X=heteroatom)bonds,owing to their inherent atom and step economy.This strategy has been recently extended to the B-H/C-H cross-dehydrogenative coupling of carboranes with arenes.However,such transformations typically either rely on the assistance of directing groups or are restricted to intramolecular processes.Herein,we report a palladium-catalyzed direct cross-dehydrogenative coupling between the B-H bond of carboranes and the C-H bond of(hetero)arenes,which affords B(9)-arylated products of o/m-carboranes in good to excellent yields with a broad substrate scope.Notably,this methodology is not limited to simple benzene rings but also delivers high yields with polycyclic aromatic hydrocarbons,five-membered heterocycles,and benzo-fused five-membered heterocycles.Control experiments reveal that B-H activation occurs preferentially over C-H activation.The high reactivity of carboranes toward Pd(II)and their steric hindrance are the keys to this successful transformation,suppressing the formation of(hetero)arene and carborane homo-coupling products,respectively.
