Internally Reuse Waste: Catalytic Asymmetric One-Pot Strecker Reaction of Fluoroalkyl Ketones, Anilines and TMSCN by Sequential Catalysis
作者:Yun-Lin Liu、Xiao-Ping Yin、Jian Zhou
DOI:10.1002/cjoc.201800001
日期:2018.4
enantioselective one‐pot facile synthesis of fluorinated Cα‐tetrasubstituted amino nitriles from α‐fluoroalkyl α‐aryl ketones, anilines, and TMSCN through a sequential p‐TsOH catalyzed ketimine formation and chiral bifunctional tertiaryamine mediated asymmetric Strecker reaction. This one‐pot approach has two important advantages. First, it greatly improves the overall yield of the synthesis of chiral Cα‐tetrasubstituted
<i>N</i>-Protecting group tuning of the enantioselectivity in Strecker reactions of trifluoromethyl ketimines to synthesize quaternary α-trifluoromethyl amino nitriles by ion pair catalysis
trifluoromethylated quaternary stereocenters with N-PMP and unexplored N-Boc trifluoromethyl ketimines catalyzed using an organophosphine dual-reagent catalyst has been developed. The enantioselectivities of the corresponding products with the same catalyst could be switched by using different N-protectinggroups (N-PMP or N-Boc). The trifluoromethyl amino nitriles were obtained in high yield and high enantioselectivity
The enantioselective organocatalytic reduction of trifluoromethyl aryl and alkyl ketoimines afforded the corresponding fluorinated amines with high chemical and stereochemical efficiency. The Lewis base catalyzed reaction with trichlorosilane led to chiral products with a trifluoromethyl group directly linked to the newly generated stereocenter typically in >90% yield and up to 98% e.e.
Amines to an end: Highly opticallyactive α‐CF3‐functionalized amines can be obtained using metal‐free reaction conditions. The method involves the transfer hydrogenation of CF3‐substituted ketimines catalyzed by 1 and reductive amination of CF3‐substituted ketones. The synthetic utility of this method was demonstrated by the synthesis of a CF3 analogue of NPS R‐568. PMP=para‐methoxyphenyl.
Ethylene Glycol: A Powerful Catalyst‐Free Medium for CC Bond‐Forming Reactions
作者:Yun‐Lin Liu、Xing‐Ping Zeng、Jian Zhou
DOI:10.1002/asia.201200289
日期:2012.8
A good EG: Ethylene glycol (EG) is a catalyst‐free medium that can promote the highly efficient Strecker reaction of α‐CF2H or α‐CF3 ketoimines and TMSCN. EG was used in several reactions, including the catalyst‐free Morita–Baylis–Hillman reaction.