62. Mechanism of Rh(III)-Catalyzed Alkylation of N-Pyrimidylindoline with Cyclopropanols: A DFT Study

Wu, X.; Bi, S.;* Chu, Y.; Liu, Y.; Jiang, Y.-Y.; Ling, B.; Yuan, X.-A.   Mol. Catal. 2020, 497, 111255. Download Link

Abstract: The reaction features combination of C–H activation and ring opening of cyclopropanol was studied with the aid of DFT calculations. With the reaction of N-pyrimidylindoline and 1-benzylcyclopropanol as an example to accomplish the alkylation, we found the order of C–H activation/ring opening is difficult to occur. Instead, the order of ring opening/C–H activation is predicted to be more reasonable, which circumvents the N→Rh bond breaking. Two catalytic cycles were suggested. The first cycle relates to the catalytic oxidation of cyclopropanol by Cu(II) to generate an intermediate product, the vinyl ketone. The mechanism mainly involves prior ring opening of cyclopropanol and β-H elimination. The second cycle relates to the product formation from the resultant intermediate product, in which the C–H activation of N-pyrimidylindoline, C– –C bond insertion of the intermediate product and protonation are included. The insights gained in this study are expected to be pertinent in other reaction systems involving combination of C–H activation and ring opening.