I2-Catalyzed Regioselective Oxo- and Hydroxy-acyloxylation of Alkenes and Enol Ethers: A Facile Access to α-Acyloxyketones, Esters, and Diol Derivatives
摘要:
I-2-catalyzed oxo-acyloxylation of alkenes and enol ethers with carboxylic acids providing for the high yield synthesis of a-acyloxyketones and esters is described. This unprecedented regioselective oxidative process employs TBHP and Et3N in stoichiometric amounts under metal-free conditions in DMSO as solvent. Additionally, I-2-catalysis allows the direct hydroxy-acyloxylation of alkenes with the sequential addition of BH3 center dot SMe2 leading to monoprotected diol derivatives in excellent yields.
In situ generation of nitrilium from nitrile ylide and the subsequent Mumm rearrangement: copper-catalyzed synthesis of unsymmetrical diacylglycine esters
作者:Jijun Chen、Ying Shao、Liang Ma、Meihua Ma、Xiaobing Wan
DOI:10.1039/c6ob02037b
日期:——
A novel in situ generation of nitrilium from a nitrileylide and the subsequent Mumm rearrangement of carboxylic acid, nitrile, and diazo compounds gave various unsymmetrical diacylglycine esters in moderate to high yields. This copper-catalyzed cascade reaction enables one-pot generation of two C–N bonds, one CO bond, and one C–H bond, with nitrogen as the only byproduct. The reaction has a broad
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).
Silver-Catalyzed Functionalization of Esters by Carbene Transfer: The Role of Ylide Zwitterionic Intermediates
作者:Riccardo Gava、M. Ángeles Fuentes、Maria Besora、Tomás R. Belderrain、Kane Jacob、Feliu Maseras、Michel Etienne、Ana Caballero、Pedro J. Pérez
DOI:10.1002/cctc.201402241
日期:2014.8
The reaction of esters with ethyl diazoacetate catalyzed by the complex [F27–TpAg(acetone)] generates α‐(acyloxy)acetates in moderate to high yields. This is a novel transformation in the context of carbene‐transfer reactions from diazo compounds that, according to experimental and theoretical data, is suggested to occur through zwitterionic intermediates.
The insertion reaction of diazocarbonyls to acids could be performed smoothly in fluorinated alcohols in the absence of metal catalyst. This new procedure allowed the chemoselective preparation of various functionalized compounds such as acyloxyesters, depsipeptides, and sulfonate, phosphonate, or boronate derivatives.
An Acid Stable Metal-Organic Framework as an Efficient and Recyclable Catalyst for the O−H Insertion Reaction of Carboxylic Acids
作者:Yingxia Wang、Hao Cui、Li Zhang、Cheng-Yong Su
DOI:10.1002/cctc.201800597
日期:2018.9.7
Although metal‐organicframeworks (MOFs) can be used in many reactions, their applications in acid involved reactions are limited due to their instability in acid environment. As a stable MOF, the Ir(III)‐porphyrin metal‐organicframework of the formula [(Hf6(μ3‐O)8(OH)2(H2O)10)2(Ir(TCPP)Cl)3]⋅solvents (Ir‐PMOF‐1(Hf)) can sustain its structure upon treatments in different pH (0–11) aqueous solutions