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.
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.
Stable organozinc compounds derived from alkyl 3-alkyl 2-(bromomethyl) propenoates reacted with ketones and aldehydes to give alpha-methylene gamma-butyrolactones in excellent yields. Different reaction parameters were studied and some transition states were proposed.
Synthesis and bioactivity of novel (3-chloro-5-(trifluoromethyl)pyridin-2-yloxy)phenyl containing acrylate and acrylonitrile derivatives
作者:Chun-Rui Yu、Long-He Xu、Song Tu、Zhi-Nian Li、Bin Li
DOI:10.1016/j.jfluchem.2006.07.011
日期:2006.12
Fifteen novel (3-chloro-5-(trifluoromethyl)pyridin-2-yloxy)phenyl containing Baylis-Hillman adduct derivatives were designed and synthesized. Evaluation of their biological activities showed that methyl 2-((3-(3-chloro-5-(trifluoromethyl)pyridin-2-yloxy)phenoxy)(phenyl)methy-l)acrylate (2g) exhibited efficient broad-spectrum fungicidal activity, with 100% control of wheat powdery mildew and cucumber downy mildew and 98% control of cucumber anthracnose at 400 g ai/ha. Some of the other title compounds 2, 3 and two Baylis-Hillman bromide intermediates (11a, 11b) had moderate to good fungicidal activity. (c) 2006 Elsevier B.V. All rights reserved.
Efficient Synthesis of 2-Methylene-3phosphorylalkanoates: Phosphorylation of Baylis–Hillman Bromides via an S<sub> <i>N</i> </sub>2-S<sub> <i>N</i> </sub>2′ Strategy
作者:Liancheng Yang、Longhe Xu、Chunrui Yu
DOI:10.1080/10426500802418545
日期:2009.8.6
A novel synthesis of 2-methylene-3-phosphorylalkanoates under mild conditions is described. Thus, Balyis-Hillman bromides react with secondary phosphine oxides or H-phosphonites in the presence of DABCO via an S(N)2-S(N)2' protocol to produce the target compounds in good yields.