Diversification of a β-lactam pharmacophore via allylic C–H amination: accelerating effect of Lewis acid co-catalyst
作者:Xiangbing (Ben) Qi、Grant T. Rice、Manjinder S. Lall、Mark S. Plummer、M. Christina White
DOI:10.1016/j.tet.2010.04.064
日期:2010.6
This report describes the use of Pd(II)/bis-sulfoxide 1 catalyzed intra- and intermolecular allylic C-H amination reactions to rapidly diversify structures containing a sensitive beta-lactam core similar to that found in the monobactam antibiotic Aztreonam. Pharmacologically interesting oxazolidinone, oxazinanone, and linear amine motifs are rapidly installed with predictable and high selectivities under conditions that use limiting amounts of substrate. Additionally, we demonstrate for the first time that intramolecular C-H amination processes may be accelerated using catalytic amounts of a Lewis acid co-catalyst [Cr(III)(salen)Cl 2]. (C) 2010 Elsevier Ltd. All rights reserved.
Allylic C−H Amination for the Preparation of <i>syn</i>-1,3-Amino Alcohol Motifs
作者:Grant T. Rice、M. Christina White
DOI:10.1021/ja9054959
日期:2009.8.26
A highly selective and general Pd/sulfoxide-catalyzed allylic C-H amination reaction en route to syn-1,3-amino alcohol motifs is reported. Key to achieving this reactivity under mild conditions is the use of electron-deficient N-nosyl carbamate nucleophiles that are thought to promote functionalization by furnishing higher concentrations of anionic species in situ. The reaction is shown to be orthogonal to classical C-C bond-forming/-reduction sequences as well as nitrene-based C-H amination methods.