Synthesis of Acylsilanes via Nickel-Catalyzed Reactions of α-Hydroxyallylsilanes
摘要:
The redox isomerization processes and tandem isomerization-aldolization reactions, mediated by nickel catalysts, offer new versatile entries to acylsilanes. For the second reaction, high diastereoselectivities, up to 98:2, have been obtained with bulky substituents on silicon.
The use of dirhodium(II) catalysts in the 1,4-hydrosilylation of alpha,beta-unsaturated ketones and aldehydes was explored. Dirhodium(II) tetrakis(perfluorobutyrate), Rh2(pfb)4, proved to be the catalyst of choice for this process, providing the corresponding silyl enol ethers in high yields.
Iodomethylzinc Phosphates: Powerful Reagents for the Cyclopropanation of Alkenes
作者:Marie-Christine Lacasse、Cyril Poulard、André B. Charette
DOI:10.1021/ja0529687
日期:2005.9.1
stereocontrol, affording the cyclopropanes of allylic and homoallylic ethers with complete conversions and up to 93% ee. A catalytic version of this reaction using 10 mol % of the chiral phosphate reagent is also disclosed.
开发了一类新的源自磷酸的类锌类化合物,并将其用于烯丙醇和醚以及未官能化烯烃的环丙烷化。使用 3,3'-二取代 BINOL 的手性磷酸可实现有效的立体控制,提供具有完全转化率和高达 93% ee 的烯丙基醚和高烯丙基醚的环丙烷。还公开了使用10mol%手性磷酸盐试剂的该反应的催化形式。
A remarkable solvent effect toward the Pd/C-catalyzed cleavage of silyl ethersElectronic supplementary information (ESI) available: characterization data and references and supplementary Tables 4 and 5. See http://www.rsc.org/suppdata/cc/b2/b211313a/
Enantioselective Dichlorination of Allylic Alcohols
作者:K. C. Nicolaou、Nicholas L. Simmons、Yongcheng Ying、Philipp M. Heretsch、Jason S. Chen
DOI:10.1021/ja202555m
日期:2011.6.1
The development of an enantioselective allylic alcohol dichlorination catalyzed by dimeric cinchona alkaloid derivatives and employing aryl iododichlorides as chlorine sources is reported. Reaction optimization, exploration of the substrate scope, and a model for stereoinduction are presented.