Synthesis of Esters by in Situ Formation and Trapping of Diazoalkanes
作者:Richard A. Squitieri、Galen P. Shearn-Nance、Jason E. Hein、Jared T. Shaw
DOI:10.1021/acs.joc.6b00408
日期:2016.7.1
method has been developed for the in situ formation and trapping of diazoalkanes by carboxylic acids to form esters. The method is applicable to a large variety of carboxylic acids using diazo compounds that are formed from the hydrazones of benzaldehydes and aryl ketones. In situ reaction monitoring with IR spectroscopy (ReactIR) was used to demonstrate that slow addition of the hydrazone to a mixture
Synthesis of Acyclic Ketones by Catalytic, Bidirectional Homologation of Formaldehyde with Nonstabilized Diazoalkanes. Application of a Chiral Diazomethyl(pyrrolidine) in Total Syntheses of Erythroxylon Alkaloids
作者:Andrew J. Wommack、Jason S. Kingsbury
DOI:10.1021/jo401377a
日期:2013.11.1
This work offers a catalytic approach to convergent ketone assembly based upon formal and tandem C–H insertion of diazoalkanes in the presence of limiting amounts of monomeric formaldehyde, which is easily generated as a gas by thermolysis of the inexpensive and abundant paraformaldehyde (∼30 USD/kg). The method forms di-, tri-, and even tetrasubstituted acetones with high efficiency, and it has streamlined
An efficient metal‐free oxidative esterification of benzylCHbonds 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
Copper-catalyzed benzylic oxidation of C(sp3)–H bonds
作者:Bo Zhang、Shou-Fei Zhu、Qi-Lin Zhou
DOI:10.1016/j.tet.2012.12.046
日期:2013.2
A selective oxidation of benzylic C(sp3)–H bonds to C(sp3)–O bonds catalyzed by copper complexes of quinoline–imine ligands was developed with peresters as oxidants under mild reaction conditions, which converted benzylic methylenes directly into benzylic alcohols and esters by means of direct C–H bond functionalization.
A protocol for the cobalt-catalyzed oxidative esterification of allylic/benzylic C(sp3)–H bonds with carboxylic acids was developed in this work. Mechanistic studies revealed that C(sp3)–H bond activation in the hydrocarbon was the turnover-limiting step and the in-situ formed [Co(III)]Ot-Bu did not engage in hydrogen atom abstraction (HAA) of a C–H bond. This protocol was successfully incorporated
在这项工作中,开发了一种用烯丙基/苄基C(sp 3)–H键与羧酸进行钴催化氧化酯化的方案。机理研究表明,碳氢化合物中的C(sp 3)-H键活化是限制周转的步骤,原位形成的[Co(III)] O t -Bu不参与氢的氢原子提取(HAA)。碳氢键。该方案已成功纳入避免使用NBS的β-大马烯酮合成途径。