Direct C-Arylation of Free (NH)-Indoles and Pyrroles Catalyzed by Ar−Rh(III) Complexes Assembled In Situ

Ar−Rh(III) pivalate complexes assembled in situ from the reaction of [RhCl(coe)2]2 (coe = cis-cyclooctene), [p-(CF3)C6H4]3P, and CsOPiv effectively catalyzed the direct C-arylation of free (NH)-indoles and (NH)-pyrroles in good yields and with high regioselectivity. The reaction displayed excellent functional group compatibility and low moisture sensitivity. Kinetics studies support a mechanism involving phosphine displacement by indole in complex 2 (resting state of the catalyst), followed by a rate-limiting C−H bond metalation.

由[RhCl(coe)₂]₂（coe = 顺式环辛烯（cis-cyclooctene））、三[4-(三氟甲基)苯基]膦与新戊酸铯（CsOPiv）原位构筑的芳基-铑(III)新戊酸酯配合物，可高效催化游离(NH)吲哚与游离(NH)吡咯的直接C-芳基化反应，且产率优良、区域选择性优异。该反应展现出优异的官能团兼容性与较低的湿度敏感性。动力学研究支持如下反应机理：作为催化剂休眠态的配合物2中的膦配体被吲哚取代，随后发生决速步的C-H键金属化过程。