A tandem Baylis–Hillman-singlet oxygen oxidation reaction for facile synthesis of γ-substituted γ-hydroxybutenolides
摘要:
A series of highly functionalised gamma-hydroxyacryl gamma-hydroxybutenolides, 2, were synthesised in 25-50% overall yields in two or three steps from 2-furfural using a tandem Baylis-Hillman-singlet oxygen oxidation reaction. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.
A tandem Baylis–Hillman-singlet oxygen oxidation reaction for facile synthesis of γ-substituted γ-hydroxybutenolides
摘要:
A series of highly functionalised gamma-hydroxyacryl gamma-hydroxybutenolides, 2, were synthesised in 25-50% overall yields in two or three steps from 2-furfural using a tandem Baylis-Hillman-singlet oxygen oxidation reaction. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.
Syn-Stereocontrolled dihydroxylation of Baylis-Hillman adducts
作者:István E. Markó、Paul R. Giles、Zdenek Janousek、Nigel J. Hindley、Jean-Paul Declercq、Bernard Tinant、Janine Feneau-Dupont、John S. Svendsen
DOI:10.1002/recl.19951140418
日期:——
The hydroxylation of Baylis-Hillmanadducts 1 is shown to proceed with high levels of diastereocontrol. A mechanistic rationale to explain this selectivity is discussed.
A Simple Route to .alpha.-Substituted-.beta.-Amino Ester Precursors of Carbapenem Antibiotics
作者:Patrick Perlmutter、Mark Tabone
DOI:10.1021/jo00125a043
日期:1995.10
A three-step process is presented for the preparation of alpha-substituted-beta-amino esters which can serve as precursors to a key intermediate in carbapenem synthesis. The pivotal reaction in this sequence involves a highly diastereoselective conjugate addition reaction. Two series of alkenoates bearing a stereogenic substituent attached to C2 were prepared and their conjugate addition reactions with benzylamine studied under several different sets of conditions. Conjugate addition of benzylamine to alkenoates 7a and 7d, in methanol at room temperature, gave adducts 8a and Sd with virtually complete anti-diastereoselectivity. These two beta-amino esters bear the correct relative stereochemistry and side chain to serve as precursors for carbapenem antibiotic synthetic intermediates. The role of the allylic substituents of the alkenoates 7a-e in determining the stereochemical outcome of these additions is discussed. These conjugate additions were explored further by the preparation and conjugate addition reactions of the alpha,beta-disubstituted alkenoates 15a and 15b. It was found that the presence of a beta-substituent led to a dramatic reduction in yield although the same anti-diastereoselectivity was maintained. The relative stereochemistry of the adducts was established by examination of the relevant coupling constants in the H-1 NMR spectra of their tetrahydro-1,3-oxazine derivatives.
A tandem Baylis–Hillman-singlet oxygen oxidation reaction for facile synthesis of γ-substituted γ-hydroxybutenolides
作者:Santoshkumar N. Patil、Benjamin E. Stephens、Fei Liu
DOI:10.1016/j.tet.2008.09.019
日期:2008.11
A series of highly functionalised gamma-hydroxyacryl gamma-hydroxybutenolides, 2, were synthesised in 25-50% overall yields in two or three steps from 2-furfural using a tandem Baylis-Hillman-singlet oxygen oxidation reaction. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.