A Convenient and Versatile Method for the Preparation of α-Hydroxymethyl Ketone Derivatives from the Corresponding Allyl Silyl Ethers or Allyl Carboxylates
作者:Yung-Son Hon、Ying-Chieh Wong、Kuo-Jui Wu
DOI:10.1002/jccs.200800134
日期:2008.8
The ozonolysis of 1-substituted allyl silyl ethers or 1-substituted allyl carboxylates followed by treatment with bases gave the corresponding α-silyloxymethyl- or a-acyloxymethyl-ketones in good yields. It is proposed to proceed via the corresponding α-silyloxy- or α-acyloxyaldehydes intermediates followed by 1,4-group migration. The results of theoretical calculations are applicable to explain the
A series of hydroxymethylketones 4a–g were obtained from the corresponding halogenomethyl ketones 2a–gvia their transformation into acetoxymethyl ketones 3a–g by 18-crown-6 catalysed substitution with NaOAc followed by Novozyme 435™ catalysed ethanolysis. This convenient chemo-enzymatic route provides a mild, heavy-metal-free alternative to the direct α-hydroxylations of methyl ketones 1a–g.
alpha-Acetoxylation of ketones catalyzed by iodobenzene using 30% aqueous hydrogen peroxide and acetic anhydride as the oxidant is an effective and economical method for the preparation of alpha-acetoxy ketones. The reaction gave the products in good yields without the addition of acetic acid and water.
Straightforward and Highly Efficient Synthesis of α-Acetoxy Ketones through Gold-Catalyzed Intermolecular Oxidation of Terminal Alkynes
作者:Weimin He、Jiannan Xiang、Chao Wu、Zhiwu Liang、Dong Yan
DOI:10.1055/s-0033-1338513
日期:——
corresponding α-acetoxy ketones throughgold-catalyzedintermolecular oxidation in the presence of 8-methylquinoline 1-oxide as the oxidant. The reaction probably proceeds through an α-oxo gold carbene intermolecular O–H insertion. A variety of terminal alkynes were efficiently converted into the corresponding α-acetoxy ketones throughgold-catalyzedintermolecular oxidation in the presence of 8-methylquinoline
Synthetic applications of the amine-base treatment in the ozonolysis of substituted-allyl silyl ethers or -allyl esters via a novel ene–diol type rearrangement
作者:Yung-Son Hon、Ying-Chieh Wong
DOI:10.1016/j.tetlet.2004.12.135
日期:2005.2
The ozonolysis of substituted-allyl silyl ethers or -allyl esters followed by treatment with bases gave the corresponding α-silyloxy ketones or α-acyloxy ketones in good yields. The reaction is proposed to proceed via a novel ene–diol rearrangement of the corresponding α-silyloxy aldehydes or α-acyloxy aldehydes intermediates.