Chiral Brønsted Acid from a Cationic Gold(I) Complex: Catalytic Enantioselective Protonation of Silyl Enol Ethers of Ketones
作者:Cheol Hong Cheon、Osamu Kanno、F. Dean Toste
DOI:10.1021/ja204331w
日期:2011.8.31
developed from a cationic gold(I) disphosphine complex in the presence of alcoholic solvent and applied to the enantioselective protonation reaction of silylenolethers of ketones. Various optically active cyclic ketones were obtained in excellent yields and high enantioselectivities, including cyclic ketones bearing aliphatic substrates at the α-position. Furthermore, the application of this Brønsted acid
Catalytic Asymmetric Cross-Couplings of Racemic α-Bromoketones with Arylzinc Reagents
作者:Pamela M. Lundin、Jorge Esquivias、Gregory C. Fu
DOI:10.1002/anie.200804888
日期:2009.1
Nickel box: The first catalytic asymmetric method for cross‐coupling arylzinc reagents with α‐bromoketones has been developed (see scheme). This stereoconvergent carbon–carbon bond‐forming process occurs under unusually mild conditions and without activators, thereby allowing the generation of potentially labile tertiary stereocenters.
A rhodium(I)-catalyzed highly enantioselective ring-opening and isomerization of cyclobutanols has been developed. The reaction provides a mild, atom-economical, and redox-neutral approach for the synthesis of chiral acyclic ketones bearing a β-tertiary stereocenter. Excellent enantioselectivities and high yields can be achieved using cyclobutanols with alkoxy substituents at the C3 position. Mechanistic
开发了铑(I)催化的环丁醇的高对映选择性开环和异构化反应。该反应为合成带有β-叔立构中心的手性无环酮提供了一种温和、原子经济且氧化还原中性的方法。使用 C3 位带有烷氧基取代基的环丁醇可以获得优异的对映选择性和高产率。机理研究表明,环丁醇仅发生分子内氢迁移,( Z )-不饱和酮中间体的形成对于实现高对映选择性至关重要。