Metal-Free Catalytic Boration at the β-Position of α,β-Unsaturated Compounds: A Challenging Asymmetric Induction
作者:Amadeu Bonet、Henrik Gulyás、Elena Fernández
DOI:10.1002/anie.201001198
日期:——
Enantiomerically enriched secondary organoboronates containing β‐carbonyl functional groups have been prepared using an unprecedented organocatalytic system (see scheme). The use of chiral tertiary phosphorus compounds induced ee values of up to 95 % in the absence of transition metals.
Direct Asymmetric Aldol Reactions of Acetone Using Bimetallic Zinc Catalysts
作者:Barry M. Trost、Elliad R. Silcoff、Hisanaka Ito
DOI:10.1021/ol0161211
日期:2001.8.9
[reaction: see text] The enantioselective aldolreaction using a novel binuclear zinccatalyst of acetone with several aldehydes gave products in good yields (62-89%) with a high level of enantioselectivity (ee = 76-92%).
Preparation of the Enantiomerically Enriched Isomers of the Odorous Cyclic EthersClarycet ®,Florol ®, andRhubafuran ® by Enzymatic Catalysis
作者:Agnese Abate、Elisabetta Brenna、Giovanni Fronza、Claudio Fuganti、Francesco G. Gatti、Stefano Serra、Enrica Zardoni
DOI:10.1002/hlca.200490075
日期:2004.4
All the enantiomericallyenriched stereoisomers of Clarycet ® (1), Florol ® (2), and Rhubafuran ® (3) were prepared by biocatalysis routes. Their absolute configurations were established, and their olfactory properties were fully evaluated.
Asymmetric dihydroxylation of α,β-unsaturated ketones provided α,β-dihydroxyketones with up to 100% ee. The Cα-O bond of these intermediates or their bis-TMS ethers, acetonides, phenylborates or orthoformiates was cleaved with SmI2, affording β-hydroxyketones. The latter can be reduced to furnish syn- or anti-configured 1,3-diols of any desired configuration.
α,β-不饱和酮的不对称二羟基化提供了高达 100% ee 的 α,β-二羟基酮。这些中间体或其双TMS 醚、丙酮化合物、苯硼酸盐或原甲酸盐的Cα-O 键被SmI2 裂解,得到β-羟基酮。后者可被还原以提供任何所需构型的顺式或反式1,3-二醇。
Catalytic Enantioselective Peroxidation of α,β-Unsaturated Ketones
作者:Xiaojie Lu、Yan Liu、Bingfeng Sun、Brittany Cindric、Li Deng
DOI:10.1021/ja802982h
日期:2008.7.1
established epoxidation pathway into a peroxidation pathway, the first efficient catalytic peroxidation has been successfully developed. Employing readily available alpha,beta-unsaturated ketones and hydroperoxides and an easily accessible cinchona alkaloid catalyst, this novel reaction will open new possibilities in the asymmetric synthesis of chiral peroxides. Under different conditions a highly enantioselective