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.
promising potentials in prostate cancer treatment has been disclosed. The key intermediates, α-hydroxy-β-keto esters, were efficiently constructed through cinchoninium-mediated asymmetric oxohydroxylation of easily accessible alkenes with potassium permanganate. Good yields and high levels of asymmetric induction are achieved. This method provides a new synthetic route to bicalutamide analogues with high
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.
Asymmetric chemo- and regiospecific addition of organozinc reagents to Baylis–Hillman derived allylic electrophiles
作者:Christoph Börner、Paul J. Goldsmith、Simon Woodward、Josep Gimeno、Serafino Gladiali、Daniela Ramazzotti
DOI:10.1039/b006943o
日期:——
The copper-catalysed SN2â² addition of
ZnR2 to allylic
(Z)-ArCHC(CH2X)(CO2Et) (X = Br, Cl,
OSO2Me) fashions only
ArCH(R)C(CH2)(CO2Et); use of a chiral ligand
gives up to 64% ee for this demanding reaction.