Size-Driven Inversion of Selectivity in Esterification Reactions: Secondary Beat Primary Alcohols
作者:Stefanie Mayr、Marta Marin-Luna、Hendrik Zipse
DOI:10.1021/acs.joc.0c02848
日期:2021.2.19
alcohols carrying large aromatic side chains with anhydrides differing in size and electronic structure have been measured. While primary alcohols react faster than secondary ones in transformations with monosubstituted benzoic anhydridederivatives, relative reactivities are inverted in reactions with sterically biased 1-naphthyl anhydrides. Further analysis of reaction rates shows that increasing substrate
alkylation, and trifluoromethanesulfonic acid (triflic acid, TfOH) was also a good catalyst. The catalytic activity of metal triflates and TfOH increased in the order La(OTf)3 < Yb(OTf)3 < TfOH < Sc(OTf)3 < Hf(OTf)4. A mechanistic study was also performed. The reaction of 1-phenylethanol (4a) in the presence of Sc(OTf)3 in nitromethane gave an equilibrium mixture of 4a and bis(1-phenylethyl) ether (54). Addition
Herein, we report a distinctive photoredox/copper dual-catalyzed esterification of benzylic C–H bonds through the combination of photoredox-mediated hydrogen atom transfer and Cu(II)-mediated radical-polar crossover. This methodology demonstrates a high functional group tolerance (>40 examples) and moderate to good yields with structurally diverse benzylic C–H substrates. Notably, stoichiometric amounts
Bu4NI-catalyzed benzylic acyloxylation of alkylarenes with aromatic aldehydes
作者:Juan Huang、Lan-Tao Li、Hong-Ying Li、Ezizjan Husan、Peng Wang、Bin Wang
DOI:10.1039/c2cc35450k
日期:——
An nBu4NI-catalyzed benzylic C–H acyloxylation of alkylarenes with readily available aromatic aldehydes has been developed. These reactions occur under mild and clean reaction conditions using tert-butyl hydroperoxide as the green terminal oxidant.