Internal Lewis acid assisted ureas: tunable hydrogen bond donor catalysts
作者:David M. Nickerson、Veronica V. Angeles、Tyler J. Auvil、Sonia S. So、Anita E. Mattson
DOI:10.1039/c2cc37073e
日期:——
The strategic incorporation of internal Lewis acids onto urea scaffolds gives rise to a family of tunable hydrogenbond donor catalysts. The nature of the Lewis acid and associated ligands affects the urea polarization, acidity, and activity in reactions of nitrocyclopropane carboxylates and nitrodiazoesters.
A catalyst-free N–H insertion/Mannich-type reaction cascade of α-nitrodiazoesters
作者:Ting Yang、Hao Zhuang、Xichen Lin、Jia-Ning Xiang、John D. Elliott、Lianghui Liu、Feng Ren
DOI:10.1016/j.tetlet.2013.05.131
日期:2013.8
A catalyst-free N-H insertion/Mannich-type reaction cascade of alpha-nitrodiazoesters with anilines has been developed to afford a variety of alpha-amino-alpha-aryl esters in 60-83% yields and under mild reaction conditions (23 or 40 degrees C). (C) 2013 Elsevier Ltd. All rights reserved.
Urea Activation of α-Nitrodiazoesters: An Organocatalytic Approach to N–H Insertion Reactions
作者:Sonia S. So、Anita E. Mattson
DOI:10.1021/ja3031054
日期:2012.5.30
The combination of a urea catalyst and an a-nitro-a-diazo ester gives rise to a reactive species able to undergo insertion into the N-H bonds of anilines. This new strategy to achieve N-H insertion reactivity is in contrast to typical metal-catalyzed conditions for the generation of carbenoids from alpha-diazocarbonyl compounds. This report includes the extension of the insertion reaction to a three-component coupling for the construction of alpha-amino-alpha-aryl esters in high yield.
Urea-Catalyzed N–H Insertion–Arylation Reactions of Nitrodiazoesters
作者:Sonia S. So、Shameema Oottikkal、Jovica D. Badjić、Christopher M. Hadad、Anita E. Mattson
DOI:10.1021/jo500698q
日期:2014.6.6
The power of hydrogen-bond donor catalysis has been harnessed to elicit and control carbene-like reactivity from nitrodiazoesters. Specifically, select ureas have been identified as effective catalysts for N-H insertion and multicomponent coupling reactions of nitrodiazoesters, anilines, and aromatic nucleophiles, thereby preparing a variety of alpha-aryl glycines in high yield. Experimental and computational studies designed to probe the plausible reaction pathways suggest that difluoroboronate ureas are particularly well-suited to catalyze reactions of nitrodiazoesters with a range of anilines through a polar reaction pathway Urea-facilitated loss of nitrite followed by addition of a nucleophile conceivably generates the observed aryl glycine products.