Acyclic Stereoselection in the Ortho Ester Claisen Rearrangement
作者:G. William Daub、James P. Edwards、Carol R. Okada、Jana Westran Allen、Claudia Tata Maxey、Matthew S. Wells、Alexandra S. Goldstein、Michael J. Dibley、Clarence J. Wang、Daniel P. Ostercamp、Steven Chung、Paula Shanklin Cunningham、Martin A. Berliner
DOI:10.1021/jo9614250
日期:1997.4.1
The ortho ester Claisen rearrangement of trisubstituted allylicalcohols exhibits significant levels of diastereoselection. In E allylicalcohols, a 1,3-diaxial interaction develops in the chairlike transition state leading to the anti isomer, rendering the reaction syn selective by a factor of 3-5 to 1. In Zallylicalcohols, the 1,3-diaxial interaction develops in the transition state leading to
Regio- and Stereospecific Formation of Protected Allylic Alcohols via Zirconium-Mediated S<sub>N</sub>2‘ Substitution of Allylic Chlorides
作者:Richard J. Fox、Gojko Lalic、Robert G. Bergman
DOI:10.1021/ja075967i
日期:2007.11.1
regio- and stereospecific SN2‘ substitution reaction between a zirconium oxo complex and allylicchloride has been achieved. The resulting allylic alcohol or TBS-protected allylic ether products were isolated in good to excellent yields with a wide range of E-allylic chlorides. A mechanism for the SN2‘ allylic substitution consistent with kinetic, stereochemical, and secondary isotope effect studies
[EN] ESTERS AS PERFUMING INGREDIENTS<br/>[FR] ESTERS EN TANT QU'INGRÉDIENTS DE PARFUM
申请人:FIRMENICH & CIE
公开号:WO2011055251A1
公开(公告)日:2011-05-12
The present invention relates to some perfuming ingredients which are esters of formula (I) wherein R1 and R2 represent each a hydrogen atom or a methyl or ethyl group; and R3 represents a C5-C8 group of formula satured or unsatured linear, branched or cyclic group.
Stable organozinc compounds derived from alkyl-3-alkyl-2-(bromomethyl)-proenoates have been prepared. NMR 13C, 1H and IR stidies show only one Z stereoisomer (no methylenic form) with a strong chelation between zinc and the carbonyl oxygen of the ester and solvated by only one solvent molecule. Hydrolysis can be achieved by two concurrent mechanisms with or without transposition.
The present invention relates γ-lactam derivatives, in particular for use as medicaments, as well as pharmaceutical formulations containing such γ-lactam derivatives. Said γ-lactam derivatives are useful in the treatment and/or prevention of asthma, hypertension, osteoporosis, sexual dysfunction and fertility disorders.