Analyzing Site Selectivity in Rh-2(esp)(2)-Catalyzed Intermolecular C-H Amination Reactions

作者：Bess Elizabeth N; DeLuca Ryan J; Tindall Daniel J; Oderinde Martins S; Roizen Jennifer L; Du Bois J^*; Sigman Matthew S

来源：Journal of the American Chemical Society, 2014, 136(15): 5783-5789.

DOI：10.1021/ja5015508

Predicting site selectivity in C-H bond oxidation reactions involving heteroatom transfer is challenged by the small energetic differences between disparate bond types and the subtle interplay of steric and electronic effects that influence reactivity. Herein, the factors governing selective Rh-2(esp)(2)-catalyzed C-H amination of isoamylbenzene derivatives are investigated, where modification to both the nitrogen source, a sulfamate ester, and substrate are shown to impact isomeric product ratios. Linear regression mathematical modeling is used to define a relationship that equates both IR stretching parameters and Hammett sigma(+) values to the differential free energy of benzylic versus tertiary C-H amination. This model has informed the development of a novel sulfamate ester, which affords the highest benzylic-to-tertiary site selectivity (9.5:1) observed for this system.

• 出版日期2014-4-16