Regio- and enantioselective formation of tetrazole-bearing quaternary stereocenters via palladium-catalyzed allylic amination

Based on palladium-catalyzed allylic amination reaction, the first general example of enantioselective formation of tetrazole-bearing quaternary stereocenter has been developed. The protocol utilizes ambivalent tetrazole and vinyl cyclic carbonates as...

Titanium and Cobalt Bimetallic Radical Redox Relay for the Isomerization of N-Bz Aziridines to Allylic Amides

Herein a bimetallic radical redox-relay strategy is employed to generate alkyl radicals under mild conditions with titanium(III) catalysis and terminated via hydrogen atom transfer with cobalt(II) catalysis to enact base-free isomerizations of N-Bz aziridines to N-Bz allylic amides. This reaction provides an alternative strategy for the synthesis of allylic amides from alkenes via a three-step sequence to accomplish a formal transpositional allylic amination.

Site-Selective Allylic C-H Amination with Aliphatic Amines

The direct coupling of olefins and alkyl amines represents the most efficient and atom-economical approach to prepare aliphatic allylamines which are fundamental building blocks. However, the method that achieves this goal while exhibiting exquisite control over the site at which the amine is introduced remains elusive. Herein, we report that the combination of a photocatalyst and a cobaloxime enables site-selective allylic C–H amination of olefins with secondary alkyl amines to afford allylic amines, eliminating the need for oxidants. This reaction proceeds by a radical-based mechanism distinct from those of existing allylic amination reactions. It affords the product resulting from cleavage of the stronger, primary allylic C–H bonds over other weaker allylic C–H bond options. DFT calculations reveal that this selectivity originates from a cobaloxime-promoted hydrogen atom transfer (HAT) process. Our method is compatible with a broad scope of alkenes, and can be extended to achieve a site- and diastereoselective amination of natural terpenes.

Palladium-catalyzed asymmetric allylic amination of a vinylethylene carbonate with N-heteroaromatics

Highly enantioselective allylic amination of a vinylethylene carbonate with N-heteroaromatics is enabled by asymmetric palladium catalysis for the synthesis of chiral acyclic nucleosides and isonucleosides.