Modified Yamaguchi reagent: Convenient and efficient esterification
A convenient and efficient esterification method that used a modified Yamaguchi reagent (2,4,6-trichlorobenzoyl chloride-4-dimethylaminopyridine) and avoided use not only of intractable acid chloride but also of acid anhydrides was proposed. The reaction mechanism was described by Fourier transform infrared spectroscopy and supported by a density functional theory calculation.
A metal-free oxidative esterification of the benzyl C-H bond
An efficient metal-free oxidative esterification of benzyl C-H bonds was developed. Using tetrabutylammonium iodide as catalyst and tert-butyl hydroperoxide as co-oxidant, benzylic substrates could react smoothly with various carboxylic acids to give the esters with good to excellent yields. The method was also suitable for the O-protection of N-Boc amino acids. The reaction mechanism was primarily investigated and a radical process was proposed. Copyright
Kinetic resolution of secondary alcohols by NHC-catalyzed oxidative esterification
Kinetic resolution of racemic secondary alcohols by oxidative esterification using carbene catalysis is described. Good to moderate selectivity has been achieved. N-Heterocyclic carbenes (NHCs) were systematically varied and several aldehydes were included in this study as acyl donors. As an oxidant, a readily available bisquinone-type system was used. Georg Thieme Verlag Stuttgart - New York.