Deaminative Arylation and Alkenyaltion of Aliphatic Tertiary Amines with Ary and Alkenylboronic Acids via Nitrogen Ylides

Transition-metal-catalyzed Suzuki-Miyaura coupling has significantly advanced C-C bond formation and has been well recognized in organic synthesis, pharmaceuticals, materials science and other fields. In this rapid development, cross coupling without transition metal catalyst is a big challenge in this field, and using widely existing tertiary amines as electrophiles to directly couple with boronic acids has great hurdles yet significant application prospects. Herein, we report an efficient and general deaminative arylation and alkenylation of tertiary amines (propargyl amines, allyl amines and 1H-indol-3-yl methane amines) with ary and alkenylboronic acids enabled by difluorocarbene under transition-metal-free conditions. Preliminary mechanism experiments suggest that in situ formed difluoromethyl quaternary amine salt, nitrogen ylide and tetracoordinate boron species are the key intermediates, the subsequent 1,2-metallate shift and protodeboronation complete the new coupling reaction.

Automated summary

Transition-metal-catalyzed Suzuki-Miyaura coupling has been widely used in organic synthesis, pharmaceuticals, materials science, and other fields. The challenge lies in achieving cross coupling without transition metal catalysts. This study reports an efficient method for arylation and alkenylation of tertiary amines using difluorocarbene under transition-metal-free conditions.