pre-equilibrium in the formation of iminodiazonium (ID) ion and that the N2 liberation from the ID ion is rate-determining. Under high azide concentration conditions, where the effective reactant is the ID ion, the reaction gave a linear Hammett plot with a ρ value of −0.50. The observed substituent effects on the rate and the product selectivity imply that path bifurcation on the way from the rate-determining
Site‐Selective Alkoxylation of Benzylic C−H Bonds by Photoredox Catalysis
作者:Byung Joo Lee、Kimberly S. DeGlopper、Tehshik P. Yoon
DOI:10.1002/anie.201910602
日期:2020.1.2
strategies for C-N and C-C bond formation. In particular, almost all methods for the incorporation of alcohols by C-H oxidation require the use of the alcohol component as a solvent or co-solvent. This condition limits the practical scope of these reactions to simple, inexpensive alcohols. Reported here is a photocatalytic protocol for the functionalization of benzylic C-H bonds with a wide range of oxygen
The (±)-1-(4-Methoxyphenyl)ethyl ester as a carboxyl protecting group
作者:Michael S. Bernatowicz、Hann-Guang Chao、Gary R. Matsueda
DOI:10.1016/0040-4039(94)88310-6
日期:1994.3
their (±)-1-(4-methoxyphenyl)ethyl (Mpe) esters in good yields by condensation with (±)-1-(4-methoxyphenyl)ethanol under mild conditions. The Mpe esters were rapidly and quantitatively cleavable by either 1% TFA in CH2Cl2 or 10% DCA in CH2Cl2, conditions which leave Boc, t-butyl ester and ether intact. An Mpe ester was removed by hydrogenolysis much more slowly than the analogous benzyl ester.