Direct catalytic asymmetric synthesis of highly functionalized tetronic acids/tetrahydro-isobenzofuran-1,5-diones via combination of cascade three-component reductive alkylations and Michael-aldol reactions
作者:Dhevalapally B. Ramachary、Mamillapalli Kishor
DOI:10.1039/c003588b
日期:——
A practical and sustainable chemical process for the synthesis of highly substituted tetrahydro-isobenzofuran-1,5-diones was achieved for the first time through asymmetric cascade Michael-aldol reaction of 4-hydroxy-3-alkyl-5H-furan-2-ones with alkyl vinyl ketones in the presence of a catalytic amount of L-proline or 9-amino-9-deoxyepiquinine/TCA. In this article, we discovered for the first time the
Enhancement of diastereoselectivity in the claisen rearrangement induced by remote stereocenters via use of sterically demanding lewis acid catalysts
作者:Robert K. Boeckman、Michael J. Neeb、Micheal D. Gaul
DOI:10.1016/0040-4039(94)02390-w
日期:1995.2
Several cases of significant enhancement in the diastereoselectivity of acyclic Claisenrearrangement of cyclohexenyl allyl ethers governed principally by remote asymmetric center(s) have been observed when Lewis acid catalysts are employed rather than the usual thermal rearrangement conditions.
Enantioselective syntheses and resolution of the key white intermediate for the synthesis of trisporic acids
作者:JoséA. Bacigaluppo、María I. Colombo、Marcelo D. Preite、Juan Zinczuk、Edmundo A. Rúveda、Joachim Sieler
DOI:10.1016/0957-4166(96)00109-7
日期:1996.4
Two asymmetric syntheses of the alkylated cyclohexenone carboxylic acid moiety, the key White intermediate (4a), of trisporic acids A, B and C are described. The syntheses feature a Michael addition in tandem with an aldol condensation as the central step. The resolution of this readily available intermediate is also described. Copyright (C) 1996 Elsevier Science
Enantioselective synthesis of the white key intermediate for the synthesis of trisporic acids
作者:José A. Bacigaluppo、María I. Colombo、Raquel M. Cravero、Manuel González-Sierra、Marcelo D. Preite、Juan Zinczuk、Edmundo A. Rúveda
DOI:10.1016/s0957-4166(00)86255-2
日期:1994.10
The asymmetric construction of the alkylated cyclohexenone carboxylic acid moiety of trisporic acids A, B and C and the syntheses of related precursors are described. The syntheses feature a Michael addition in tandem with an aldol condensation as the central step.