Copper-catalyzed intramolecular radical amination of tertiary C(sp³)–H bonds to access α-quaternary pyrrolidines

Herein, we describe a Cu(I)/phosphoric acid catalyzed intramolecular radical tertiary C(sp(3))-H amination of N-chlorosulfonamide, providing an applicable route to the pyrrolidine structural motifs bearing an alpha-quaternary stereocenter (>20 examples with up to 94 % yield). Mechanistic studies indicate that the reaction involves an intramolecular 1,5-hydrogen atom transfer process to form the key tertiary C-centered radical followed by a C-N bond formation. The corresponding enantioselective amination is accordingly disclosed by Cu(I)/chiral phosphoric acid catalyst to afford the chiral products with up to 81 % enantiomeric excess (ee). This strategy is anticipated to facilitate the development of tertiary C(sp(3))-H functionalization.