Use of 1,3-Dioxin-4-ones and Related Compounds in Synthesis. XLIV. Asymmetric Aldol Reaction of 4-Trimethylsiloxy-6-methylene-1,3-dioxines: Use of Tartaric Acid-Derived (Acyloxy)borane Complex as the Catalyst.
Use of 1,3-Dioxin-4-ones and Related Compounds in Synthesis. XLIV. Asymmetric Aldol Reaction of 4-Trimethylsiloxy-6-methylene-1,3-dioxines: Use of Tartaric Acid-Derived (Acyloxy)borane Complex as the Catalyst.
Enantioselective Synthesis of Pyranofuranone Moieties of Manoalide and Cacospongionolide B by Enzymatic and Chemical Approach
作者:Margherita De Rosa、Annunziata Soriente、Guido Sodano、Arrigo Scettri
DOI:10.1016/s0040-4020(00)00122-8
日期:2000.3
Two synthetic sequences leading to the pyranofuranone moieties of Manoalide and Cacospongionolide B in enantiomerically enriched forms are reported. The key steps involve either an enantioselective aldol condensation or an enzymatic resolution.
Nonlinear effects and auto-induction in the asymmetric aldol condensation of synthetic equivalents of acetoacetic esters
作者:Rosaria Villano、Margherita De Rosa、Concetta Salerno、Annunziata Soriente、Arrigo Scettri
DOI:10.1016/s0957-4166(02)00539-6
日期:2002.9
(+)-NLEs, have been detected in the Ti(IV)/BINOL complex-mediated catalytic asymmetric aldol reaction of three different masked acetoacetate esters. The use of a different procedure for the catalyst preparation disclosed the occurrence of aldol condensation of Chan's diene through an auto-inductive process.
A convenient catalytic procedure for the highly enantioselective aldol condensation of O-silyldienolates
作者:Margherita De Rosa、Maria Rosaria Acocella、Rosaria Villano、Annunziata Soriente、Arrigo Scettri
DOI:10.1016/s0957-4166(03)00494-4
日期:2003.9
In the presence of catalytic amount of chiral Ti(OiPr)(4)/BINOL (0.08 equiv.) the asymmetric aldol condensation of 6-methyl-4H-[1,3]-dioxin-4-one-derived silyloxydienes takes place in high yields and enantiomeric excesses with aromatic. heteroaromatic, Unsaturated and aliphatic aldehydes. Notable amplification of enantiomeric excesses have been obtained by using enantioenriched catalytic systems. (C) 2003 Elsevier Ltd. All rights reserved.
Enantioselective aldol condensation of O-silyl dienolates to aldehydes mediated by chiral BINOL–titanium complexes
作者:Margherita De Rosa、Annunziata Soriente、Arrigo Scettri
DOI:10.1016/s0957-4166(00)00259-7
日期:2000.8
Chiral BINOL-titanium complexes have been shown to catalyze enantioselective aldol reactions between dioxinone derivatives and a set of aldehydes. The aldol adducts are isolated in good yields and high enantioselectivities. A range of substitution patterns on the O-silyl dienolate is possible: alkyl and benzyl substituents are tolerated. A simple reaction protocol is described and provides an efficient alternative to the well-known methods for conducting enantioselective Mukaiyama aldol reactions. (C) 2000 Elsevier Science Ltd. All rights reserved.