Unique Regioselectivity in the C(sp³)–H α‑Alkylation of Amines: The Benzoxazole Moiety as a Removable Directing Group

The benzoxazol-2-yl- substituent was found to act as a removable activating and directing group in the Ir-catalyzed alkylation of C­(sp³)–H bonds adjacent to nitrogen in secondary amines. It can be easily introduced by oxidative coupling or by an S_NAr reaction, and it can be removed by hydroxide or by hydride reduction. For 1,2,3,4-tetra­hydroiso­quinolines, activation exclusively takes place in the 3-position. A variety of activated as well as unactivated terminal olefins are suitable reaction partners.