Insertion of Nitriles into Zirconocene 1-aza-1,3-diene Complexes: Chemoselective Synthesis of N-H and N-Substituted Pyrroles
作者:Shasha Yu、Meijun Xiong、Xin Xie、Yuanhong Liu
DOI:10.1002/anie.201407221
日期:2014.10.20
insertion of nitriles into zirconocene‐1‐aza‐1,3‐diene complexes provides an efficient, chemoselective, and controllable synthesis of N‐H and N‐substitutedpyrroles upon acidic aqueous work‐up. The outcome of the reaction (that is, the formation of N‐H or N‐substitutedpyrroles) results from the different cyclization patterns, which depend on the relative stability and reactivity of the enamine–imine
A Highly Enantioselective Lewis Basic Organocatalyst for Reduction of <i>N</i>-Aryl Imines with Unprecedented Substrate Spectrum
作者:Zhouyu Wang、Xiaoxia Ye、Siyu Wei、Pengcheng Wu、Anjiang Zhang、Jian Sun
DOI:10.1021/ol060112g
日期:2006.3.2
L-Pipecolinic acid derived formamides have been developed as highly efficient and enantioselective Lewis basic organocatalysts for the reduction of N-aryl imines with trichlorosilane. Catalyst 4b afforded high isolated yields (up to 98%) and enantioselectivities (up to 96%) under mild conditions with an unprecedented substrate spectrum.
Catalytic 1,3-Difunctionalisation of Organic Backbones through a Highly Stereoselective, One-Pot, Boron Conjugate-Addition/Reduction/Oxidation Process
作者:Cristina Solé、Amolak Tatla、Jose A. Mata、Andrew Whiting、Henrik Gulyás、Elena Fernández
DOI:10.1002/chem.201102081
日期:2011.12.9
enantioselectivity provided by the CuI catalyst modified with Josiphos‐ and Mandyphos‐type ligands has been examined. The oxidative substitution of the boryl unit with a hydroxyl group proceeds with complete retention of configuration at the Cβ‐atom. In parallel, the stoichiometric reduction of the imino or carbonyl group provides a second stereogenic centre. Depending on the nature of the reducing reagent
Combo effects: The first example of an iron‐mediated β‐boration of activated olefins is reported. The origin and the benefits of the catalytic activity associated with the presence of iron have been questioned and carefully studied. The iron system has been compared to the organocatalytic β‐boration of α,β‐unsaturated esters, ketones, and imines (see scheme; acac=acetylacetonate, pin=pinacol).
A highly efficient Cu‐catalyzed CB bond formation has been developed to transform 1‐azadienes into β‐imino boronate esters when reacted with bis(pinacolato)diboron and a base. A series of functionalized imines and oximes were found to react under very mild conditions. A further oxidation protocol enabled β‐iminoalcohols to be selectively synthesized.