New Potentially Chelating Chiral Magnesium Amide Bases for Use in Enantioselective Deprotonation Reactions
作者:William Kerr、Michael Middleditch、Allan Watson
DOI:10.1055/s-0030-1259282
日期:2011.1
to prepare novel chiral magnesium bisamide reagents. These amide bases were subsequently applied within asymmetric deprotonation reactions to probe the potential for chelation-assisted selectivity enhancement. Good levels of selectivity could be achieved (up to 87:13 e.r. (R:S)) across a range of prochiral cyclohexanone substrates when employing a thiophene-derived magnesium bisamide complex.
合成了一系列手性仲胺,结合了 5 或 6 元杂环,并用于制备新型手性镁双酰胺试剂。随后将这些酰胺碱应用于不对称去质子化反应中,以探索螯合辅助选择性增强的潜力。当使用噻吩衍生的镁双酰胺复合物时,可以在一系列前手性环己酮底物上实现良好的选择性(高达 87:13 er (R:S))。
Enantioselective desymmetrization of prochiral ketones via an organocatalytic deprotonation process
The first desymmetrization of 4-substituted cyclohexanones by organocatalytic asymmetric deprotonation at low catalyst loading is reported. The combination of N,O-bis(trimethylsilyl)acetamide (BSA) and chiralquaternaryammoniumaryloxide salts has been used as an efficientorganocatalyticsystem to provide silyl enolates in high yields and with modest ee.
Towards energetically viable asymmetric deprotonations: selectivity at more elevated temperatures with C2-symmetric magnesium bisamides
作者:Linsey S. Bennie、William J. Kerr、Michael Middleditch、Allan J. B. Watson
DOI:10.1039/c0cc04939e
日期:——
A novel chiral magnesium bisamide has enabled the development of effective asymmetric deprotonation protocols at substantially more elevated temperatures. This new, structurally simple, C2-symmetric magnesium complex displays excellent levels of asymmetric efficiency and energy reduction in the synthesis of enantioenriched enol silanes.
Enantioselective Approaches to Potential MetAP-2 Reversible Inhibitors
作者:Vincent Rodeschini、Pierre Van de Weghe、Emmanuel Salomon、Céline Tarnus、Jacques Eustache
DOI:10.1021/jo047858h
日期:2005.3.1
Enantioselective deprotonation of 4-substituted cyclohexanones and highly stereoselective conjugate addition of higher order mixed cuprates were the key steps in a concise synthesis of fumagalone-related molecules. The origin of the (low) biological activity of the new compounds as compared to fumagalone is briefly discussed.
Synthesis of butenolides via enantioselective deprotonation of protected 4-hydroxycyclohexanone
作者:Marek Majewski、Nicholas M. Irvine、John MacKinnon
DOI:10.1016/0957-4166(95)00231-d
日期:1995.8
Enantioselective synthesis of two butenolides (4S, 6R)-2,3-Dihydroaquilegiolide and (4S, 6S)-2,3-Dihydromenisdaurilide based on deprotonation of 4-tert-butyldimethyl-siloxycyclohexanone with a chiral lithium amide base is described.