A Phosphetane Catalyzes Deoxygenative Condensation of α-Keto Esters and Carboxylic Acids via P<sup>III</sup>/P<sup>V</sup>═O Redox Cycling
作者:Wei Zhao、Patrick K. Yan、Alexander T. Radosevich
DOI:10.1021/ja511889y
日期:2015.1.21
A small-ring phosphacycle is found to catalyze the deoxygenative condensation of α-keto esters and carboxylic acids. The reaction provides a chemoselective catalytic synthesis of α-acyloxy ester products with good functional group compatibility. Based on both stoichiometric and catalytic mechanistic experiments, the reaction is proposed to proceed via catalytic P(III)/P(V)═O cycling. The importance
Metal‐free photochemical carbene‐transfer reactions of tosylhydrazones were developed under blue light irradiation at room temperature. This reaction constructs C−X (X=C, N, O, S) bonds and cyclopropanes from readily available and stable starting materials.
Systematic Evaluation of Sulfoxides as Catalysts in Nucleophilic Substitutions of Alcohols
作者:Sebastian Motsch、Christian Schütz、Peter H. Huy
DOI:10.1002/ejoc.201800907
日期:2018.9.9
Out of an in‐depth study of a range of sulfinyl compounds in the transformation of alcohols into chloro alkanes emerged (2‐methoxyphenyl)methyl sulfoxide as optimal Lewis base catalyst. While this catalyst allowed the synthesis of benzylic chlorides in turn‐over numbers up to 50, aliphatic alcohols are non‐suitable substrates due to competing Pummerer rearrangement.
Tropylium-Catalyzed O–H Insertion Reactions of Diazoalkanes with Carboxylic Acids
作者:Claire Empel、Thanh Vinh Nguyen、Rene M. Koenigs
DOI:10.1021/acs.orglett.0c04069
日期:2021.1.15
describe the application of a nonbenzenoid aromatic carbocation, namely tropylium, as an organic Lewis acid catalyst in O–H functionalization reactions of diazoalkanes with benzoic acids. The newly developed protocol is applicable to a wide range of diazoalkane and carboxylic acid substrates with excellent efficiency (43 examples, up to 99% yield).
A Nonmetal Approach to α-Heterofunctionalized Carbonyl Derivatives by Formal Reductive XH Insertion
作者:Eric J. Miller、Wei Zhao、Jonathan D. Herr、Alexander T. Radosevich
DOI:10.1002/anie.201205604
日期:2012.10.15
Keeping it organic: A direct synthesis of α‐alkoxy and α‐amino ester derivatives by direct reductive coupling of widely available, stable α‐keto esters and protic pronucleophiles is described (see scheme; X=OR, NR2). The method serves as a convenient nonmetal alternative to XHinsertion by diazo decomposition.
使其保持有机状态:已描述了通过广泛可得的,稳定的α-酮酸酯和质子性亲核试剂的直接还原偶联直接合成α-烷氧基和α-氨基酯衍生物的方法(参见方案; X = OR,NR 2)。该方法可作为重氮分解中XH插入的便捷非金属替代方法。