Diiodine–Triethylsilane System: Reduction of N-Sulfonyl Aldimines to N-Alkylsulfonamides
作者:Jin Jiang、Lili Xiao、Yu-Long Li
DOI:10.1055/s-0040-1706544
日期:2021.2
using these reagents are easy to operate and require mild reaction conditions. Molecular iodine and a hydrosilane were used to reduce N-sulfonyl aldimines to the corresponding N-alkylsulfonamides. This transformation is a practicalmethod for the synthesis of N-alkylsulfonamides.
The P-chirogenic organocatalysts were found to promote the enantioselective aza-MoritaâBaylisâHillman reaction of ketimines derived from acyclic α-keto esters. In the P-chirogenic organocatalyzed aza-MBH reactions, α,α-disubstituted α-amino acid derivatives were obtained in high yields with high enantioselectivities (up to 97% ee).
N-p-tolylsulfonyl-2-arylglycinates in high yields by a combination of aluminum(III) chloride and diphenylsilane under operating conditions in which diphenylsilane was added to the pre-formed substrate-aluminum(III) chloride complex in dichloromethane and the mixture stirred. The case of an exactly equivalent amount of aluminum(III) chloride as the substrate resulted in good results.
Bifunctional Thiourea–Ammonium Salt Catalysts Derived from Cinchona Alkaloids: Cooperative Phase-Transfer Catalysts in the Enantioselective Aza-Henry Reaction of Ketimines
An efficient enantioselective aza-Henry reaction of aryl α-ketoester-derived ketimines has been realized by using bifunctional thiourea–ammonium salt phase-transfercatalysts, which were derived from quinine. A variety of aryl α-ketoester-derived N-Ts ketimines were investigated, and the corresponding products were obtained in high to excellent yields (up to 99%) with good to high enantioselectivities
Organocatalyzed Formal [2 + 2] Cycloaddition of Ketimines with Allenoates: Facile Access to Azetidines with a Chiral Tetrasubstituted Carbon Stereogenic Center
An enantioselective organocatalyzed aza-MBH-type reaction of ketimines and allenoates has been developed. The present formal [2 + 2] cycloaddition produces highly functionalized azetidines with a chiral tetrasubstituted carbon stereogenic center in good to excellent yields and high enantioselectivities.