Base-promoted selective β-fragmentation of homoallylamines
摘要:
A selective beta-fragmentation of homoallylamines with the combination of iodobenzene diacetate, iodine, and sodium acetate is reported. The desired carbon-carbon bond cleavage proceeded via a radical beta-scission pathway under mild conditions with good functional group tolerance. (C) 2010 Elsevier Ltd. All rights reserved.
The carboxyl group (COOH) is an omnipresent functional group in organic molecules, and its direct catalytic activation represents an attractive synthetic method. Herein, we describe the first example of a direct catalytic nucleophilic activation of carboxylicacids with BH3·SMe2, after which the acids are able to act as carbon nucleophiles, i.e. enolates, in Mannich-type reactions. This reaction proceeds
The first nickel(0)-catalyzed [2 + 2 + 1] carbonylative cycloaddition reaction of imines and alkynes or norbornene has been achieved by employing phenyl formate as a CO source. With this method, a variety of N-benzenesulfonyl, -tosyl, and -phosphoryl-substituted γ-lactams can be prepared in good to high yields.
Aza-Morita–Baylis–Hillman reactions catalyzed by a cyclopropenylidene
作者:Xun Lu、Uwe Schneider
DOI:10.1039/c6cc06201f
日期:——
Catalysis using a bis(dialkylamino)cyclopropenylidene (BAC) has been developed, which relies on a formal umpolung activation of Michael acceptor pro-nucleophiles.
A multicomponent approach to the synthesis of N-sulfonyl β2,3-amino esters
作者:Erwan Le Gall、Stéphane Sengmany、Issa Samb、Sabrina Benakrour、Christopher Colin、Antoine Pignon、Eric Léonel
DOI:10.1039/c3ob42353k
日期:——
The multicomponent synthesis of α,β-disubstituted N-sulfonyl β-amino esters is described. It involves a zinc-mediated, cobalt-catalyzed three-component reaction between sulfonylimines, acrylates and organic bromides. A possible mechanism is proposed, emphasizing the intermediate formation of an organocobalt as the initiator of a Mannich-like process.
Expanding the Utility of Brønsted Base Catalysis: Biomimetic Enantioselective Decarboxylative Reactions
作者:Yuanhang Pan、Choon Wee Kee、Zhiyong Jiang、Ting Ma、Yujun Zhao、Yuanyong Yang、Hansong Xue、Choon-Hong Tan
DOI:10.1002/chem.201100687
日期:2011.7.18
of simple esters, the use of them as nucleophiles in directasymmetric transformations is a long‐standing challenge in synthetic organic chemistry. Nature approaches this difficulty through a decarboxylative mechanism, which is used for polyketide synthesis. Inspired by nature, we report guanidine‐catalyzed biomimetic decarboxylative CC and CN bond‐formation reactions. These highly enantioselective