Absolute configuration of eldanolide, the wing gland pheromone of the male African sugar cane borer, Eldana saccharina (Wlk.) syntheses of its (+) and (−) enantiomers.
Stereospecificity in allergic contact dermatitis to simple substituted methylene lactones derivatives
作者:Henri Mattes、Kaoru Hamada、Claude Benezra
DOI:10.1021/jm00394a003
日期:1987.11
The enantiomers of beta,gamma-dimethyl- and beta-methyl-alpha-methylene-gamma-butyrolactones have been synthesized stereospecifically from glutamic acid and beta-hydroxy isobutyric acid, respectively. Guinea pigs have been sensitized (Freund complete adjuvant technique) and tested to them. Both enantiomers of beta-methyl lactone as well as (+)-beta,gamma-dimethyl lactone induced enantiospecific allergic contact dermatitis (ACD); in turn, (-)-beta,gamma-dimethyl lactone showed no specificity. An interpretation is proposed.
Highly regio- and stereoselective reductions of spiroketals
Highly regio- and stereoselective reductions of the spiroketals have been achieved by DIBAH and silane-Lewis acid. The key factors of these selectivities were attributed to steric hindrance of alpha-methyl group at spiroketal and to vicinal ether oxygens for bidentate chelation.
Asymmetric 1,4-Hydrosilylations of α,β-Unsaturated Esters
作者:Bruce H. Lipshutz、Jeff M. Servesko、Benjamin R. Taft
DOI:10.1021/ja049135l
日期:2004.7.14
Complexing catalytic amounts of CuH with a nonracemic JOSIPHOS or SEGPHOS ligand, together with stoichiometric PMHS, leads to exceedingly efficient and highly enantioselective 1,4-reductions of beta,beta-disubstituted enoates and lactones. An unprecedented substrate-to-ligand ratio of 7700:1 for this type of reaction is documented.
MATTES, HENRI;HAMADA, KAORU;BENEZRA, CLAUDE, J. MED. CHEM., 30,(1987) N 11, 1948-1951