Asymmetric oxidation of 3-alkyl-1,2-cyclopentanediones. Part 1: 3-Hydroxylation of 3-alkyl-1,2-cyclopentanediones
摘要:
3-Alkyl-1,2-cyclopentanediones undergo asymmetric 3-hydroxylation with the Sharpless Ti-complex resulting in enantiomeric 3-hydroxy carbonyl compounds with ee up to 95% in yields of 22-40%. (C) 2002 Elsevier Science Ltd. All rights reserved.
Asymmetric oxidation of 3-alkyl-1,2-cyclopentanediones. Part 1: 3-Hydroxylation of 3-alkyl-1,2-cyclopentanediones
摘要:
3-Alkyl-1,2-cyclopentanediones undergo asymmetric 3-hydroxylation with the Sharpless Ti-complex resulting in enantiomeric 3-hydroxy carbonyl compounds with ee up to 95% in yields of 22-40%. (C) 2002 Elsevier Science Ltd. All rights reserved.
A method for the aerobic cascade oxidation of cyclopentane-1,2-diones using metal porphyrins as catalysts, yielding hydroxydiacids 2, ketoacid 3 and diketoacids 4 which are the intermediates of important biologically active compounds is reported. This method is operationally simple and can be employed under ambient conditions.
3-Substituted 1,2-cyclopentanediones 1 were transformed to 2-substituted 5-oxotetrahydrofuran-2-carboxylic acids 2 using a catalytic process with 0.2-0.3 equivalent of Ti(OiPr)(4)/tartaric ester/tBuO0H complex in up to 72% isolated yield and up to 94% ee. Different functional groups in the 3-alkyl substituent of 1 like, hydroxy, ether, Boc-amino and ester groups are tolerated. Boc-aminomethyl substitu.ents lead to beta-amino acid analogues and Boc-aminoethyl substituent to gamma-amino acid analogues as well as spiro-lactonelactams. A direct, two-step procedure for homocitric acid synthesis is described.
Heterogeneous platinum catalytic aerobic oxidation of cyclopentane-1,2-diols to cyclopentane-1,2-diones
A method for the aerobic oxidation of cyclopentane-1,2-diols to the corresponding diketones over a commercial heterogeneous Pt/C catalyst is described. Unsubstituted and 3- or 4-substituted cyclopentane-1,2-diols are oxidized to 1,2-dicarbonyl compounds in good yields under the reported optimized reaction conditions (atmospheric air, 1 mol % of catalyst, 1 equiv of LiOH, aqueous solvents and 60 degrees C temperature). The method is applicable for producing cyclopentane-1,2-diketones in a scalable manner. (C) 2014 Elsevier Ltd. All rights reserved.
Asymmetric oxidation of 1,2-cyclopentanediones
作者:Anne Paju、Tõnis Kanger、Tõnis Pehk、Margus Lopp
DOI:10.1016/s0040-4039(00)01106-0
日期:2000.8
Cyclic 3-alkyl-1,2-cyclopentanediones undergo a direct asymmetric oxidation with the DET/Ti(OiPr)(4)/tBuOOH oxidative system, resulting in enantiomeric alpha-hydroxy compounds and ring-cleaved hydroxylated acids (lactones) up to 95% ee. (C) 2000 Elsevier Science Ltd. All rights reserved.
ESTERS OF (2-HYDROXY-3-OXO-CYCLOPENT-1-ENYL) ACETIC ACID AND THEIR USE FOR PREPARING (-)-R-HOMOCITRIC ACID GAMMA-LACTONE, (+)-S-HOMOCITRIC ACID GAMMA-LACTONE AND THE CORRESPONDING (-)-R-HOMOCITRIC ACID AND (+)-S-HOMOCITRIC ACID SALTS
申请人:Lopp Margus
公开号:US20090187041A1
公开(公告)日:2009-07-23
Archiral (2-hydroxy-3-oxo-cyclopent-1-enyl) acetic acid) alkyl, alkylphenyl and phenyl esters, and a simple and efficient method for the synthesis of both enantiomers of homocitric acid gamma-lactone and the corresponding salts from these esters are described. The method is based on asymmetric oxidation of esters, and the steps of basic and acidic hydrolysis and final acidic lactonization of the homocitric acid into homocitric acid gamma-lactone. The homocitric acid salts are obtained after basic treatment of homocitric acid gamma-lactone. The esters, conditions and reagents used in chemical conversion and separating products are important constituents affording efficient and simple method for production of homocitric acid gamma-lactone and homocitric acid salts.