Expedient synthesis of β,β-disubstituted α-methylenepropionates
摘要:
Baylis-Hillman alcohols are excellent sources of the allylic halides ArCH=CH(CH2X)(CO2R) (X = Br. Cl: R-1= Me, Et. Bu'). The Z double bond isomers are attained in high isomeric purity (> 14: 1. ZIE). The halides are chemo- and regiospecifically transformed into the acrylates (ArCHR2)C(=CH2)(CO2R1) on treatment with Zn(R-2)(2) (R-2 =Me. Et, CH2TMS, CH(2)SiMe(2)Ome) or PrZnBr- in the presence of catalytic amounts of copper(1) salts (0.5-20 mol%) in high yield. (C) 2004 Elsevier Ltd. All rights reserved.
Mapping the Mechanism of Nickel-Ferrophite Catalysed Methylation of Baylis-Hillman-Derived S<sub>N</sub>2′ Electrophiles
作者:Andrew Novak、Maria José Calhorda、Paulo Jorge Costa、Simon Woodward
DOI:10.1002/ejoc.200801029
日期:2009.2
presence of ferrophite ligands has been investigated computationally and experimentally. The sense and degree of enantioselectivity attained is independent of both the leaving group and the isomeric structure of the initial allylic halide. DFT studies support the selective formation of a limited number of energetically favoured anti and syn π-allyl intermediates. The observed regio- and enantioselectivity
The stereoselective synthesis of (2Z)-2-(chloromethyl)alk-2-enoates has been achieved efficiently and in high yields and in short reaction times from Baylis-Hillman adducts, 3-hydroxy-2-methylene-alkanoates, by treatment with FeCl3 or InCl3 at room temperature. (C) 2004 Elsevier Ltd. All rights reserved.
Expedient synthesis of β,β-disubstituted α-methylenepropionates
作者:Kallolmay Biswas、Christoph Börner、Josepe Gimeno、Paul J. Goldsmith、Daniella Ramazzotti、Angela L.K. So、Simon Woodward
DOI:10.1016/j.tet.2004.12.002
日期:2005.2
Baylis-Hillman alcohols are excellent sources of the allylic halides ArCH=CH(CH2X)(CO2R) (X = Br. Cl: R-1= Me, Et. Bu'). The Z double bond isomers are attained in high isomeric purity (> 14: 1. ZIE). The halides are chemo- and regiospecifically transformed into the acrylates (ArCHR2)C(=CH2)(CO2R1) on treatment with Zn(R-2)(2) (R-2 =Me. Et, CH2TMS, CH(2)SiMe(2)Ome) or PrZnBr- in the presence of catalytic amounts of copper(1) salts (0.5-20 mol%) in high yield. (C) 2004 Elsevier Ltd. All rights reserved.
A Mild and Efficient Method for Chlorination ofBaylis–Hillman Adducts Using PPh3/Cl3CCONH2
A new and convenient stereoselective synthesis of (Z)-2-(chloromethyl)alk-2-enoates has been achieved from Baylis–Hillman adducts by treatment with PPh3/Cl3CCONH2 at room temperature. The synthesis can proceed under mild and acid-free conditions to form the products in high yields.