The O-Acylation of Ketone Enolates by Allyl 1<i>H</i>-Imidazole-1-carboxylate Mediated with Boron Trifluoride EtherateA Convenient Procedure for the Synthesis of Substituted Allyl Enol Carbonates
作者:Barry M. Trost、Jiayi Xu
DOI:10.1021/jo7016313
日期:2007.11.1
A convenient access to substituted allylenol carbonates was established through the reaction of ketone enolates with the complex of allyl 1H-imidazole-1-carboxylates and boron trifluoride etherate.
Ligand Controlled Highly Regio- and Enantioselective Synthesis of α-Acyloxyketones by Palladium-Catalyzed Allylic Alkylation of 1,2-Enediol Carbonates
作者:Barry M. Trost、Jiayi Xu、Thomas Schmidt
DOI:10.1021/ja8038954
日期:2008.9.10
The palladiumcatalyzed decarboxylative asymmetric allylic alkylation of allyl 1,2-enediol carbonates 1 can decompose to either alpha-hydroxyketones 3 or alpha-hydroxyaldehydes 4. The product distribution is largely controlled by the ligand. Using Lnaph in DME we exclusively obtained the ketone product in good to excellent yields and high enantiomeric excesses. The reaction proceeds under extremely
Palladium-Catalyzed Asymmetric Allylic Alkylation of 2-Acylimidazoles as Ester Enolate Equivalents
作者:Barry M. Trost、Konrad Lehr、David J. Michaelis、Jiayi Xu、Andreas K. Buckl
DOI:10.1021/ja103771w
日期:2010.7.7
A broad range of highly enantioenriched 2-acylimidazoles are synthesized by palladium-catalyzed decarboxylative asymmetricallylicalkylation (DAAA) of 2-imidazolo-substituted enol carbonates. The enantioenriched 2-acylimidazole products can easily be converted to the corresponding carboxylic acid, ester, amide, and ketone derivatives with complete retention of the enantiopurity. The synthetic utility
Enantioselective Synthesis of Tertiary α-Hydroxyketones from Unfunctionalized Ketones: Palladium-Catalyzed Asymmetric Allylic Alkylation of Enolates
作者:Barry M. Trost、Raffael Koller、Benjamin Schäffner
DOI:10.1002/anie.201203663
日期:2012.8.13
Aiming high: The title reaction for the synthesis of tertiaryα‐hydroxyketones is reported. Protected 1,2‐enediol carbonates, the starting materials, were accessed from simple and readily available enol carbonates. Highly functionalized tertiaryα‐hydroxyketones can be obtained in high yield with excellent enantioselectivity using this method (see scheme).
Synthesis of Tertiary Amines through Extrusive Alkylation of Carbamates
作者:Guoliang Zhang、David Favela、Winston L. Chow、Rishab N. Iyer、Alexander J. Pell、David E. Olson
DOI:10.1021/acs.orglett.2c02516
日期:2022.8.26
Basic amines are key elements of many biologically active natural products and pharmaceuticals. Given their inherent reactivity, it is often necessary to protect basic amines during target-directed synthesis, which results in wasteful protection/deprotection sequences. We report a step-economical approach enabling the protection of secondary amines as carbamates prior to their conversion to tertiary
碱性胺是许多具有生物活性的天然产物和药物的关键元素。鉴于其固有的反应性,在靶向合成过程中通常需要保护碱性胺,这会导致保护/脱保护序列的浪费。我们报告了一种分步经济的方法,能够在仲胺通过 CO 2的正式挤出转化为叔胺之前将其保护为氨基甲酸酯。该方法适用于 iboga 生物碱 (±)-conodusine A 和 (±)-conodusine B 的合成。