21383-12-0Relevant academic research and scientific papers
Mechanistic Study of a Re-Catalyzed Monoalkylation of Phenols
Lehnherr, Dan,Wang, Xiao,Peng, Feng,Reibarkh, Mikhail,Weisel, Mark,Maloney, Kevin M.
, p. 103 - 118 (2018/11/06)
A mechanistic study of a rhenium catalyzed monoalkylation of phenols is described. Reaction kinetics reveals a zero-order dependence on both alkene and phenol and a half order dependence on catalyst. Isotopic labeling studies, competition experiments, kinetic isotope effects, and Hammett analysis together afford experimental data consistent with a reversible C-H activation step and an irreversible hydrometalation process. The turnover-limiting step is identified as catalyst deaggregation. NMR studies of binary mixtures of catalyst and a single substrate (alkene or phenol) as well as those of reaction mixtures identify potential intermediates and off-cycle species. Despite the numerous Re complexes formed in these mixtures, the overall reaction is both high yielding and highly selective for monoalkylation of phenols.
