Diastereoselective synthesis of α,β-unsaturated systems
摘要:
Functionalized Z-vinylic tellurides were used in substitution reactions with lower order cyanocuprates leading to alpha, beta-unsaturated ketones and esters in good yields. In the case of acyclic tellurides, the product was obtained in high diastereoselectivity. The control of the stereoselectivity was achieved by simple change of the reaction temperature. (C) 2005 Elsevier Ltd. All rights reserved.
IBS-Catalyzed Oxidative Rearrangement of Tertiary Allylic Alcohols to Enones with Oxone
作者:Muhammet Uyanik、Ryota Fukatsu、Kazuaki Ishihara
DOI:10.1021/ol9013188
日期:2009.8.6
A 2-iodoxybenzenesulfonic acid (IBS)-catalyzed oxidative rearrangement of tertiary allylic alcohols to enones with powdered Oxone in the presence of potassium carbonate and tetrabutylammonium hydrogen sulfate has been developed.
methods for oxidative rearrangement of tertiary allylic alcohols to β-substituted α,β-unsaturated carbonyl compounds employing oxoammonium salts are described. The methods developed are applicable to acyclic substrates as well as medium membered ring substrates and macrocyclic substrates. The counteranion of the oxoammonium salt plays crucial roles on this oxidative rearrangement.
The novel catalytic method for the oxidativerearrangement of tertiary allylicalcohols to beta-substituted alpha,beta-unsaturated ketones is described. TEMPO/NaIO4-SiO2 causes facile and efficient oxidativerearrangement of various acyclic substrates as well as medium-sized and macrocyclic substrates.
Making Mixtures to Solve Structures: Structural Elucidation via Combinatorial Synthesis
作者:Nigel A. Lengkeek、Paul F. Greenwood、Blake Nguyen、George A. Koutsantonis、Matthew J. Piggott
DOI:10.1021/cc900134t
日期:2010.1.11
A domino Horner-Wadsworth-Emmons olefination strategy has been used to prepare homologous series of (polyen)ones, and through combinatorial elaboration, corresponding families of highly branched hydrocarbons. Gas chromatography-mass spectrometry of the mixtures has enabled the rapid and unambiguous identification of several highly branched alkanes of geochemical importance. This is the first example of the use of combinatorial synthesis for the elucidation of structural connectivity.
A stereoselective synthesis of .alpha.,.beta.-unsaturated ketones involving the reactions of organocuprates with .beta.-alkylthio .alpha.,.beta.-enones