Asymmetric Cyanation of Aldehydes, Ketones, Aldimines, and Ketimines Catalyzed by a Versatile Catalyst Generated from Cinchona Alkaloid, Achiral Substituted 2,2′-Biphenol and Tetraisopropyl Titanate
Full investigation of cyanation of aldehydes, ketones, aldimines and ketimines with trimethylsilyl cyanide (TMSCN) or ethyl cyanoformate (CNCOOEt) as the cyanide source has been accomplished by employing an in situ generated catalyst from cinchona alkaloid, tetraisopropyl titanate [Ti(OiPr)4] and an achiral modified biphenol. With TMSCN as the cyanide source, good to excellent results have been achieved
A simple and efficient synthesis of N-sulfonyl ketimines through a Pd-catalyzedcross-coupling reaction between organoboronic acids and tosylbenzimidoyl chlorides under mild conditions has been developed.
Thermal Ring Expansion of 2-Sulfonylimidoyl-1-phthalimidoaziridines into <i>N</i>
-Sulfonylimidazoles
作者:Aleksandr Stukalov、Vitalii V. Suslonov、Mikhail A. Kuznetsov
DOI:10.1002/ejoc.201701806
日期:2018.4.17
Di‐, tri‐substituted, and spiro‐fused 2‐sulfonylimidoyl‐1‐phthalimidoaziridines are transformed to di‐, tri‐substituted, and condensed N‐sulfonylimidazoles upon thermolysis. This ringexpansion is accompanied by an intramolecular 1,3‐sulfonyl shift.
Construction of Tetrasubstituted Carbon by an Organocatalyst: Cyanation Reaction of Ketones and Ketimines Catalyzed by a Nucleophilic N-Heterocyclic Carbene
cyanation reaction of ketones and ketimines having lower reactivity than aldehydes and aldimines with TMSCN in the presence of N-heterocyclic carbene prepared from 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride and potassium tert-butoxide, as a nucleophilic organocatalyst, is described. These cyanations of ketones and ketimines afford the corresponding products in good yields under mild reaction conditions
Asymmetric Conjugate Addition of Malonate Esters to α,β-Unsaturated<i>N</i>-Sulfonyl Imines: An Expeditious Route to Chiral δ-Aminoesters and Piperidones
作者:Miguel Espinosa、Gonzalo Blay、Luz Cardona、José R. Pedro
DOI:10.1002/chem.201302687
日期:2013.10.25
The asymmetric conjugate addition of malonate esters to α,β‐unsaturated N‐sulfonyl imines is catalyzed by PyBOX/La(OTf)3 complexes in the presence of 4 Å MS. The reaction gives the corresponding E enamines bearing a stereogenic center at the allylic position with good yields and enantiomeric ratios up to 97:3. This reaction provides a synthetic entry to chiral δ‐aminoesters and piperidones.