Catalytic Asymmetric 1,3‐Dipolar Cycloaddition of β‐Fluoroalkylated α,β‐Unsaturated 2‐Pyridylsulfones with Nitrones for Chiral Fluoroalkylated Isoxazolidines and γ‐Amino Alcohols
across various aromatic and aliphatic nitrones in the presence of a chiral NiII/bis(oxazoline) catalyst. The process was tuned by 4 Å molecular sieves, chiralbis(oxazoline) ligands, reaction solvents, and temperature. A wide array of optically pure fluoroalkylated isoxazolidines were obtained, thus facilitating the asymmetric synthesis of an enantioenriched α‐trifluoromethylated γ‐amino alcohol in gram‐scale
Facile Synthesis of Fully Substituted Dihydro-β-carbolines via Brønsted Acid Promoted Cascade Reactions of α-Indolyl Propargylic Alcohols with Nitrones
作者:Lu Wang、Xin Xie、Yuanhong Liu
DOI:10.1021/ol302695p
日期:2012.12.7
Brønsted acid promoted cyclizations of α-indolyl propargylic alcohols with nitrones is described. The use of nitrones bearing alkenyl or electron-rich aryl groups as the R4 substituent dramatically switches the reaction pathway to afford tetrasubstituted alkenes and amines, which is assumed to proceed through a rearrangement reaction involving N–O bond cleavage and 1,2-migration of the R4 group to an adjacent
Selective Cyclization of Arylnitrones to Indolines under External Oxidant-Free Conditions: Dual Role of Rh(III) Catalyst in the C–H Activation and Oxygen Atom Transfer
作者:Ramesh B. Dateer、Sukbok Chang
DOI:10.1021/jacs.5b01065
日期:2015.4.22
The first example of Rh(III)-catalyzed cyclization of arylnitrones to indolines under external oxidant-free conditions is presented. An intermolecular coupling of arylnitrones with internal alkynes is made possible by the dual role of the Cp*Rh(III) catalyst mediating both the C-H bond activation and O-atom transfer. Synthetically important and pharmacologically privileged indoline derivatives were obtained
介绍了在无外部氧化剂条件下,Rh(III) 催化芳基硝酮环化成二氢吲哚的第一个例子。Cp*Rh(III) 催化剂在介导 CH 键活化和 O 原子转移的双重作用下,使芳基硝酮与内部炔烃的分子间偶联成为可能。以良好的收率和高非对映选择性获得了合成上重要且药理学上有特权的二氢吲哚衍生物。
Rh<sup>III</sup>-Catalyzed site-selective amidation with nitrone as a traceless directing group: an approach to functionalized arylaldehydes
作者:Hong Deng、Hongji Li、Wenge Zhang、Lei Wang
DOI:10.1039/c7cc05297a
日期:——
An efficient Rh-catalyzed site-selective amidation of nitrones with 1,4,2-dioxazol-5-ones has been developed. The reaction can tolerate a number of groups and generates functionalized aldehydes in good yields. The significance of the amidation is highlighted by the late-stage transformation of the formed aldehydes.