Synthesis and Stereochemistry-Activity Relationship of small Bacteriocin, an Autoinducer of the Symbiotic Nitrogen-Fixing Bacterium Rhizobium leguminosarum
摘要:
The four stereoisomers of small bacteriocin, an autoinducer of the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum, were synthesized via a versatile methodology for 3'-hydroxyacyl homoserine lactones based on the Nagao asymmetric aldol reaction. The synthetic isomers were much less effective at inhibiting the growth of R. leguminosarum RBL5523 than the natural isomer, showing the importance of stereochemistry for activity.
Synthesis and Stereochemistry-Activity Relationship of small Bacteriocin, an Autoinducer of the Symbiotic Nitrogen-Fixing Bacterium Rhizobium leguminosarum
摘要:
The four stereoisomers of small bacteriocin, an autoinducer of the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum, were synthesized via a versatile methodology for 3'-hydroxyacyl homoserine lactones based on the Nagao asymmetric aldol reaction. The synthetic isomers were much less effective at inhibiting the growth of R. leguminosarum RBL5523 than the natural isomer, showing the importance of stereochemistry for activity.
Transition metal complexes of N-heterocyclic carbenes, method of preparation and use in transition metal catalyzed organic transformations
申请人:Organ G. Michael
公开号:US20070073055A1
公开(公告)日:2007-03-29
The present invention relates to catalysts of transition metal complexes of N-heterocyclic carbenes, their methods of preparation and their use in chemical synthesis. The synthesis, ease-of-use, and activity of the compounds of the present invention are substantial improvements over in situ catalyst generation. Further, the transition metal complexes of N-heterocyclic carbenes of the present invention may be used as precatalysts in metal-catalyzed cross-coupling reactions.
Ni-Catalyzed Sonogashira Coupling of Nonactivated Alkyl Halides: Orthogonal Functionalization of Alkyl Iodides, Bromides, and Chlorides
作者:Oleg Vechorkin、Delphine Barmaz、Valérie Proust、Xile Hu
DOI:10.1021/ja906040t
日期:2009.9.2
Ni-catalyzed Sonogashira coupling of nonactivated, beta-H-containing alkyl halides, including chlorides, is reported. The coupling is tolerant to a wide range of functional groups, including ether, ester, amide, nitrile, keto, heterocycle, acetal, and aryl halide, in both coupling partners. The coupling can be selective for a specific C-X bond (X = I, Br, Cl) and allows for orthogonal functionalization
The reactivity of the highly functionalized copper, zinc reagents RCu(CN)ZnI toward 1-haloalkynes and acetylenic esters
作者:Ming Chang P. Yeh、Paul Knochel
DOI:10.1016/s0040-4039(01)80511-6
日期:1989.1
The highlyfunctionalizedorganometallics RCu(CN)ZnI 1 react efficiently with 1-haloalkynes providing polyfunctionalized alkynes in high yields. This method has been used to prepare a pheromone of the Amathes c-nigrum in 3 steps and 64% overall yield. The reagents 1 also add in the presence of an excess of Me3SiCl to acetylenic esters to afford polyfunctionalized C—silylated ethylenic esters. In the