New intermediates, process for their preparation, and their use for the
申请人:Rhone-Poulenc Nutrition Animale
公开号:US05266708A1
公开(公告)日:1993-11-30
New intermediates and processes for the preparation of vitamins A and E, which are the acetals of 5,6-dihalo-3-methyl-3-hydroxyhexanal or of 6-halo-3-hydroxy-3-methyl-5-hexenal or 3-methyl-3-hydroxy-5-hexenal, as well as processes for making the intermediates. After dehydrohalogenation and dehydration these intermediates are condensed directly with .beta.-ionone or with 2-methyl-2-heptene-6-one to synthesize vitamins A and E respectively.
SmI<sub>2</sub>-Promoted Oxidation of Aldehydes in the Presence of Electron-Rich Heteroatoms
作者:Amos B. Smith、Dongjoo Lee、Christopher M. Adams、Marisa C. Kozlowski
DOI:10.1021/ol027095p
日期:2002.12.1
[GRAPHICS]The Evans-Tishchenko reaction provides an efficient and practical solution for the oxidation of aldehydes possessing sensitive electron-rich heteroatoms to the corresponding esters. Careful selection of the sacrificial beta-hydroxy ketone provides considerable subsequent flexibility to access the desired carboxylic acid.