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.
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).
Regio- and Enantioselective Pd-Catalyzed Allylic Alkylation of Ketones through Allyl Enol Carbonates
作者:Barry M. Trost、Jiayi Xu
DOI:10.1021/ja043472c
日期:2005.3.9
ketones occurs asymmetrically in the presence of chiral ligands previously developed in this group. With 2-methylcyclohexanone, asymmetric regioselective alkylation occurs at the more substituted carbon without complications of polyalkylation. Alkylation to create quaternary centers in indanones and benzonabenone occurs in much higher ee than using tin or lithiumenolates. The sense of enantioinduction in
在该组先前开发的手性配体存在下,Pd 催化的烯醇烯丙基碳酸酯重组为烯丙基化酮是不对称的。使用 2-甲基环己酮,不对称区域选择性烷基化发生在更多取代的碳上,而没有多烷基化的并发症。在茚满酮和苯并苯酮中产生四元中心的烷基化发生的 ee 比使用锡或烯醇锂高得多。四氢萘酮中的对映诱导意义与烯醇化锡和锂的例子相反。第一次,在高 ee (78-99%) 的情况下,第三中心的不对称创建发生了。该反应与使用锂或烯醇锡之间的不同结果表明可能涉及不同的机制。
Construction of tertiary chiral centers by Pd-catalyzed asymmetric allylic alkylation of prochiral enolate equivalents
作者:Yusuke Kita、Yoshitaka Numajiri、Noriko Okamoto、Brian M. Stoltz
DOI:10.1016/j.tet.2015.05.092
日期:2015.9
The palladium-catalyzed decarboxylative allylic alkylation of enol carbonates derived from lactams and ketones is described. Employing these substrates with an electronically tuned Pd catalyst system trisubstituted chiral centers are produced. These stereocenters have been previously challenging to achieve using Pd complex/chiral P-N ligand systems. (C) 2015 Elsevier Ltd. All rights reserved.