Complementary diastereoselectivity in the intermolecular addition of titanium and magnesium naphtholates to asymmetric lactaldehydes
作者:Robin G. F. Giles、Cynthia A. Joll、Melvyn V. Sargent、D. Matthew G. Tilbrook
DOI:10.1039/a901456j
日期:——
S)-2-(1′-ethoxyethoxy)propanal 4 afforded solely (1S, 2R, 1″R or S)-1-(7′-benzyloxy-4′,5′-dimethoxy-1′-hydroxy-2′-naphthyl)-2-(1″-ethoxyethoxy)propan-1-ol 5, being the erythro product arising from anti addition. Complementary reaction of the naphthol 3 as its bromomagnesium naphtholate with aldehyde 4 gave rise solely to the alternative (1R, 2R, 1″R or S) diastereomer 6 . The naphthol 3 was prepared through the completely
Phosphane ligands with two binding sites of differing hardness for enantioselective Grignard cross coupling
作者:Andreas Terfort、Henri Brunner
DOI:10.1039/p19960001467
日期:——
A series of new, chiral phosphanes is presented, individual members of which were designed to serve as ligands in transition-metal mediated asymmetric Grignard cross coupling reactions. These ligands are characterized by a side chain containing one or two oxygen atoms with the capacity to act as binding sites for the incoming Grignard reagent. A number of structural parameters for the compounds was varied to learn about the reaction mechanism. Most of the ligands were tested in two cross coupling reactions, the formation of 3-phenylbut-1-ene and of 2,2′-dimethyl-1,1′-binaphthyl, respectively. Although both systems gave modest enantiomeric excesses it was not possible to make a comparison of their respective abilities.
Process for the production of alkanediol derivative
申请人:Ihara Chemical Industry Co., Ltd.
公开号:US06720463B1
公开(公告)日:2004-04-13
The present invention provides a process for producing an alkanediol derivative represented by the general formula (II) from an ester compound represented by the general formula (I), safely without giving rise to racemization.
The present invention lies in a process for producing an alcohol derivative represented by the following general formula (II):
(wherein R2 and R3 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; X is a hydrogen atom or a protecting group for hydroxyl group; and n is 0 or 1), which process comprises reducing an ester compound represented by the following general formula (I):
(wherein R1 is an alkyl group having 1 to 4 carbon atoms; and R2, R3, X and n have the same definitions as given above) with sodium borohydride in a mixed solvent of at least one kind of solvent selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons and alicyclic hydrocarbons and a primary alcohol.
PROCESS FOR THE PRODUCTION OF ALKANEDIOL DERIVATIVES
申请人:IHARA CHEMICAL INDUSTRY CO., LTD.
公开号:EP1146032A1
公开(公告)日:2001-10-17
The present invention provides a process for producing an alkanediol derivative represented by the general formula (II) from an ester compound represented by the general formula (I), safely without giving rise to racemization.
The present invention lies in a process for producing an alcohol derivative represented by the following general formula (II):
(wherein R2 and R3 are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; X is a hydrogen atom or a protecting group for hydroxyl group; and n is 0 or 1), which process comprises reducing an ester compound represented by the following general formula (I):
(wherein R1 is an alkyl group having 1 to 4 carbon atoms; and R2, R3, X and n have the same definitions as given above) with sodium borohydride in a mixed solvent of at least one kind of solvent selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons and alicyclic hydrocarbons and a primary alcohol.