Asymmetric addition of trimethylsilylcyanide to N-benzylimines catalyzed by recyclable chiral dimeric V(V) salen complex
摘要:
Chiral dimeric vanadium (V) salen complex (10 mol%) derived from 5,5-Methylene di-[(S,S)-{N-(3-tert-butyl salicylidine)-N'-(3',5'-di-tert-butyl salicylidene)]-1,2-cyclohexanediamine] with vanadyl suphate followed by auto oxidation was used as efficient catalyst for enantioselective Strecker reaction of N-benzylimines with TMSCN at -30 degrees C. Excellent yield (92%) of alpha-aminonitrile and high chiral induction was achieved (ee up to 94%) in case of 2-methoxy substituted N-benzylimines in 10 h. The catalytic system worked well up to four cycles with retention of enantioselectivity. (C) 2010 Published by Elsevier B. V.
Synthesis of α-Amino Nitriles from Carbonyl Compounds, Amines, and Trimethylsilyl Cyanide: Comparison between Catalyst-Free Conditions and the Presence of Tin Ion-Exchanged Montmorillonite
作者:Jiacheng Wang、Yoichi Masui、Makoto Onaka
DOI:10.1002/ejoc.200901323
日期:2010.3
In the absence of catalysts, the three-component, one-pot synthesis of α-aminonitriles proceeded using various aldehydes and ketones together with amines and trimethylsilyl cyanide (TMSCN) in high yields under neat conditions at room temperature. The addition order of the reagents had a significant influence on the yields of the desired α-aminonitriles. In contrast, when tin ion-exchanged montmorillonite
A Remarkable Titanium-Catalyzed Asymmetric Strecker Reaction using Hydrogen Cyanide at Room Temperature
作者:Balamurugan Ramalingam、Abdul Majeed Seayad、Li Chuanzhao、Marc Garland、Kazuhiko Yoshinaga、Manabu Wadamoto、Takushi Nagata、Christina L. L. Chai
DOI:10.1002/adsc.201000462
日期:2010.9.10
Close to perfect enantioselectivity (up to 98% ee) is obtained for the formation of amino nitriles using hydrogen cyanide (HCN) as the cyanide source at room temperature for the first time. In an operationally simple process, the catalyst generated from a partially hydrolyzed titanium alkoxide (PHTA) and (S)‐N‐salicyl‐β‐amino alcohol ligand, catalyzes the cyanation of imines in a short reaction time
作者:Antony J. Davies、Michael S. Ashwood、Ian F. Cottrell
DOI:10.1080/00397910008087127
日期:2000.3
Abstract A convenient scaleable process for the preparation of substituted phenylglycines 2 by a modified Strecker reaction is described. Bisulfite-mediated addition of benzylamine and cyanide anion to substituted benzaldehydes 3 gave the aminonitriles 4 which were hydrolysed in two steps to the N-protected amino acid 1. Debenzylation using catalytic transfer hydrogenation gave the title compounds
Water-Mediated Strecker Reaction: An Efficient and Environmentally Friendly Approach for the Synthesis of <font>α</font>-Aminonitriles <i>via</i> a Three-Component Condensation
The synthesis of -aminonitriles by a direct three component Strecker reaction has been achieved in water, which is found to be an inexpensive, non-toxic and eco-friendly reaction medium for the nucleophilic addition. This protocol is effective to a wide variety of substrates with different functional groups and does not require the use any other catalyst.
TITANIUM COMPOUND AND PROCESS FOR ASYMMETRIC CYANATION OF IMINES
申请人:Seayad Abdul Majeed
公开号:US20100185000A1
公开(公告)日:2010-07-22
The present invention relates to titanium catalysts for asymmetric synthesis reactions produced by bringing a reaction mixture obtained by contacting water and a titanium alkoxide into contact with an optically active ligand represented by the general formula (a), wherein R
1
, R
2
, R
3
, and R
4
are independently a hydrogen atom, an alkyl group, or the like, and A* represents a group with two or more carbon atoms having an asymmetric carbon atom or axial asymmetry. The invention further relates to a process for asymmetric cyanation of imines, wherein the process comprises reacting an imine with a cyanating agent in the presence of the titanium catalyst.