Formal Aza‐Wacker Cyclization by Tandem Electrochemical Oxidation and Copper Catalysis
作者:Xiangli Yi、Xile Hu
DOI:10.1002/anie.201814509
日期:2019.3.26
In oxidative electrochemical organic synthesis, radical intermediates are often oxidized to cations on the way to final product formation. Herein, we describe an approach to transform electrochemically generated organic radical intermediates into neutral products by reaction with a metalcatalyst. This approach combines electrochemical oxidation with Cu catalysis to effect formal aza‐Wacker cyclization
N-aryl-4-vinyloxazolidin-2-ones. The success of the reaction depends on the acidity of the aniline and requires in situ conversion of the dicarbonate into carbamate carbonate by nucleophilicattack of the aniline conjugate base followed by palladium-catalyzed intramolecular cyclization.
In situ screening to optimize variables in organic reactions
申请人:University of Nebraska
公开号:US20030148257A1
公开(公告)日:2003-08-07
A biphasic process for rapid screening of organic reactions comprising monitoring relative rates of parallel organic reactions. The screening process is suitable to determine the efficacy of different reactants, process conditions, and process enhancers such as catalysts or promoters. The biphasic process also allows multiple samples to be analyzed/monitored simultaneously. In addition because enzymes are used to monitor the reaction product in this invention, when that product is chiral and an enantio-discriminating enzyme is used to monitor the product, in addition to the relative rates, enantioselectivities of a set of parallel organic reactions can also be determined. The monitoring is done in situ and thus removal of aliquots for separate testing is unnecessary
In situ enzymatic screening (ISES) of P,N-ligands for Ni(0)-mediated asymmetric intramolecular allylic amination
作者:David B. Berkowitz、Weijun Shen、Gourhari Maiti
DOI:10.1016/j.tetasy.2004.06.052
日期:2004.9
An in situ enzymatic screening (ISES) approach to rapid catalyst evaluation recently pointed to Ni(0) as a new candidate transition metal for intramolecular allylic amination. This led to further exploration of chiral bidentate phosphine ligands for such transformations. Herein, a variety of P,N-ligands are examined for this Ni(0)-chemistry, using a model reaction leading into the vinylglycinol scaffold. On the one hand, an N,N-bis(2-diphenylphosphinoethyl)alkylamine ('PNP') ligand proved to be the fastest ligand yet seen for this Ni(0)-transformation. On the other, phosphinooxazoline (PHOX) ligands of the Pfaltz-Helmchen-Williams variety gave the highest enantioselectivities (up to 51% ee) among P,N-ligands examined. (C) 2004 Elsevier Ltd. All rights reserved.
HAYASHI, TAMIO;YAMAMOTO, AKIHIRO;ITO, YOSHIHIKO, TETRAHEDRON LETT., 28,(1987) N 41, 4837-4840