Lewis acid-promoted α-hydroxy β-dicarbonyl to α-ketol ester rearrangement
摘要:
The decarbomethoxylation reaction of a substituted alpha-hydroxy-alpha-carbomethoxy pentacyclic substituted ketone, used as an advanced intermediate in the synthesis of the alkaloid aspidophytine, can be effected by heating with MgI2 in CH3CN. The reaction was shown to proceed by a novel a-hydroxy beta-dicarbonyl to alpha-ketol ester rearrangement. It was possible to isolate a carbonate intermediate in 75% yield, thereby providing support for the proposed pathway. (c) 2006 Elsevier Ltd. All rights reserved.
Various β-dicarbonylcompounds can be hydroxylated as their silyl enol ethers by -chloroperbenzoic acid (MCPBA).
各种β-二羰基化合物可以被-氯过苯甲酸(MCPBA)羟基化为它们的甲硅烷基烯醇醚。
Iron-catalyzed hydroxylation of β-ketoesters with hydrogen peroxide as oxidant
作者:Dongmei Li、Kristin Schröder、Bianca Bitterlich、Man Kin Tse、Matthias Beller
DOI:10.1016/j.tetlet.2008.07.157
日期:2008.10
The hydroxylation of β-ketoesters was studied using simple iron catalysts and 30 wt % hydrogenperoxide as the terminal oxidant. The highest activity and yield were achieved in the presence of iron(III) chloride. Cyclic β-ketoesters could be smoothly hydroxylated in 75–90% yield. For linear β-ketoester and β-ketoamide, the chloro-substituted products were obtained.
Synthesis of 2-Hydroxy-3-oxocarboxylic Esters From the Corresponding α,β-Unsaturated Esters by a Simple One-Step Procedure
作者:D. H. G. Crout、D. L. Rathbone
DOI:10.1055/s-1989-27142
日期:——
A convenient one-step synthesis of 2-alkyl-2-hydroxy-3-oxocarboxylic esters by potassium permanganate oxidation of the corresponding readily available α,β-unsaturated esters is described. Preparation of the latter by the phosphonate modification of the Wittig reaction is also reported.
Synthesis of Tetrasubstituted Furan Derivatives by Condensation of 1,3-Diketones with Cyclic α-Hydroxy-β-oxo Esters
作者:Barhiem Schickmous、Jens Christoffers
DOI:10.1002/ejoc.201402388
日期:2014.7
alicyclic and heterocyclic α-hydroxy-β-oxo esters under acidic conditions [0.1 equiv. cerium(III) salt in AcOH]. With [b]-annulated 4-acyl-3-hydroxy-5-methylfuran-2-carboxylates as common intermediates, the reaction proceeded along different pathways depending on the starting materials used: Alicyclic α-hydroxy-β-oxo esters gave cycloalkane-annulated furans as products. The ester group was lost after
Hydroxylation of Beta-Dicarbonyls with Zirconium Catalysts
申请人:Casalnuovo Albert Loren
公开号:US20100185014A1
公开(公告)日:2010-07-22
The present invention pertains to a process for preparing a compound of Formula I that is achiral, racemic or enantiomerically enriched at the hydroxylation center indicated by *
comprising contacting a compound of Formula II
with an oxidant selected from oxygen, hydrogen peroxide, peracids or alkyl hydroperoxides in the presence of a zirconium complex, wherein R
1
, R
2
and R
3
are as defined in the disclosure. This invention also pertains to zirconium complexes useful in this procedure comprising zirconium and a ligand of Formula III or its enantiomer
wherein J, R
6
and n are as defined in the disclosure. This invention further pertains to a compound of Formula III or its enantiomer.