Iron- Catalyzed C( sp2)-H and C( sp3) -H Arylation by Triazole Assistance

Modular 1,2,3-triazoles enabled iron-catalyzed CH arylations with broad scope. The novel triazole-based bidentate auxiliary is easily accessible in a highly modular fashion and allowed for user-friendly iron-catalyzed C(sp(2))H functionalizations of arenes and alkenes with excellent chemo- and diastereoselectivities. The versatile iron catalyst also proved applicable for challenging C(sp(3))H functionalizations, and proceeds by an organometallic mode of action. The triazole-assisted CH activation strategy occurred under remarkably mild reaction conditions, and the auxiliary was easily removed in a traceless fashion. Intriguingly, the triazole group proved superior to previously used auxiliaries.