Ni(ii)-Catalyzed enantioselective Mukaiyama–Mannich reaction between silyl enol ethers and cyclic N-sulfonyl α-ketiminoesters

Abstract

The first Ni(ii)-catalyzed Mukaiyama–Mannich reaction of cyclic N-sulfonyl α-ketiminoesters with silyl enol ethers was realized and provided enantioenriched benzofused sultams containing a quaternary α-amino ester.

Highly Enantioselective Construction of Fully Substituted Stereocenters Enabled by In Situ Phosphonium-Containing Organocatalysis

“…The mechanistic reaction cycle of this decarboxylative addition is also believed to follow the general mechanism described in the literature, , and the detailed reaction pathway is shown in Figure . First, the nucleophilic addition of phosphine to the electron-deficient allenoate generates the zwitterion B , which can further deprotonate the incoming β-keto acid 2a to form an ion-pair I that contains the phosphonium intermediate C and the anionic form of the nucleophile D .…”

“…This decarboxylative Mannich-type reaction, which mimics the reaction pathway of natural biosynthesis, was shown to be one of the most straightforward and efficient approaches for producing functionalized chiral amines . The reaction was typically catalyzed by Lewis acid and chiral amine catalysts, and important advances have been achieved so far. , Nevertheless, the asymmetric versions on decarboxylative addition of sterically hindered ketimines particularly as cyclic N -sulfonyl ketimines are very rare − , despite the fact that such process provides a powerful tool for preparing biologically valuable but synthetically challenging N-containing fully substituted stereocenters, which are also significant building blocks in numerous bioactive compounds (Scheme ). Furthermore, to the best of our knowledge, there is no report on an asymmetric decarboxylative addition process in application of phosphine-containing organic base catalysis.…”

Further Developments and Applications of Oxazoline-Containing Ligands in Asymmetric Catalysis

“…However, the α-difluorinated acetophenone derived silyl enol ether gave the corresponding benzosultam 758 in only 21% yield with a 30% ee value. 280 …”

A convenient approach to difluoromethylated all-carbon quaternary centers via Ni(ii)-catalyzed enantioselective Michael addition

“…4 b ,6 Therefore, the development of efficient and concise method for the construction of all-carbon quaternary stereocenter featuring CF 2 H group is of great significance and highly desirable for medicinal research. As a continuation of our ongoing research to explore efficient and economical asymmetric methodology, 10 we herein report our recent findings on the addition of β-difluoromethyl nitroalkene with 2-acetyl azarenes.…”