Direct Catalytic Asymmetric Mannich-Type Reaction of Benzyl Isocyanide: Stereoselective Synthesis of 1,2-Diarylethylenediamines
作者:Keiji Tamura、Naoya Kumagai、Masakatsu Shibasaki
DOI:10.1002/ejoc.201500336
日期:2015.5
A directcatalyticasymmetricMannich-typereaction of benzyl isocyanide using a CuI catalyst and N-(diphenylthiophosphinoyl)imines was developed. The simultaneous activation strategy by soft–soft interaction was the key to promote the reaction using a weakly acidic pronucleophile, benzyl isocyanide. The spontaneous cyclization of the Mannich adduct afforded the corresponding enantioenriched imidazolines
开发了使用 CuI 催化剂和 N-(二苯基硫代膦酰基) 亚胺的苄基异氰化物的直接催化不对称曼尼希型反应。通过软-软相互作用的同时激活策略是使用弱酸性亲核试剂苄基异氰化物促进反应的关键。曼尼希加合物的自发环化得到相应的对映体富集的咪唑啉,它可能是各种 1,2-二芳基乙二胺的前体。
Syntheses of effectively-shielded N-heterocyclic carbene ligands
作者:Shin Ando、Hirofumi Matsunaga、Tadao Ishizuka
DOI:10.1016/j.tet.2012.12.036
日期:2013.2
A novel type of N-heterocyclic carbene ligand, with a bicyclic motif at the non-carbenic carbons of an imidazolin-2-ylidene core, has been developed. This type of ligand formed an air and moisture stable silver complex even with N,N'-dimethyl NHC. Allylic arylation with a Grignard reagent catalyzed by copper complexes of the NHC ligands proceeded preferentially at the gamma-position, indicating the effective steric shielding ability of this framework. (C) 2012 Elsevier Ltd. All rights reserved.