development of the highly diastereoselective catalytic synthesis of glycidic acid derivatives via Darzens reaction is described. The reaction of α-chloroesters and amides with aromatic aldehydes smoothly proceeds in the presence of a quaternary ammonium salt as a phase-transfer catalyst to give the corresponding cis and trans desired products in satisfactory yields, respectively.
Gadaj; Kowalkowska; Jonczyk, Polish Journal of Chemistry, 2008, vol. 82, # 3, p. 577 - 584
作者:Gadaj、Kowalkowska、Jonczyk
DOI:——
日期:——
Adger, Brian M.; Barkley, James V.; Bergeron, Sophie, Journal of the Chemical Society. Perkin transactions I, 1997, # 23, p. 3501 - 3507
作者:Adger, Brian M.、Barkley, James V.、Bergeron, Sophie、Cappi, Michael W.、Flowerdew, Benjamin E.、Jackson, Mark P.、McCague, Ray、Nugent, Thomas C.、Roberts, Stanley M.
DOI:——
日期:——
A Novel Darzens type reaction promoted by tributylstannylcarbamate
Stannylcarbamate 1 proved to be a selective agent for generating organotin(IV) enolates from alpha-halo ketones. Thus, a Darzens reaction was achieved under mild and neutral conditions. The reaction took place without any side reactions and even with aliphatic alpha-halo ketones bearing enolizable alpha'-hydrogens. Various types of alpha,beta-epoxy ketones and esters were obtained in this one-pot reaction. The stereoselectivity of the reaction was influenced by changing the halogen substituent of the alpha-halo ketones and by additives. Moreover, the present method could be applied to gamma- and delta-halo ketones as enolate precursors, and five- and six-membered cyclic compounds were obtained.
Convenient synthesis of t-butyl Z-3-substituted glycidates under conditions of phase-transfer catalysis
作者:Andrzej Jonczyk、Tomasz Zomerfeld
DOI:10.1016/s0040-4039(03)00234-x
日期:2003.3
Reactions of mixtures of t-butyl E- and Z-3-substituted glycidates 1a-h with 50% aq. sodium hydroxide and a catalyst, benzyltriethylammonium chloride, TEBAC in dichloromethane (phase-transfer catalysis, PTC led to preferential hydrolysis of the E-isomers to afford pure (90-98%) t-butyl Z-3-substituted glycidates 1a-i in good yields; PTC cleavage of glycidates additionally substituted at C-2, 1g or C-3, 1h,i suggests that an aryl group in the Z isomers hampers attack of HO- on the carbonyl carbon atom. As described in the literature, the diastereoselective PTC synthesis of Z-3-substituted glycidates and glycidonitriles consists of fast hydrolysis of E isomers present in mixtures with Z ones. (C) 2003 Elsevier Science Ltd. All rights reserved.