Transition metal-free direct C(sp2)-H thiocyanation of 2-iminothiazolines at room temperature

Abstract

We present a metal-free and highly efficient protocol for N-chlorosuccinimide (NCS)-mediated C-H thiocyanation of 2-iminothiazolines using potassium thiocyanate (KSCN). This transformation proceeds under mild conditions, requiring only 1.2 equivalents of NCS at ambient temperature in an aerobic atmosphere. The developed protocol demonstrates excellent efficiency for C-H thiocyanation enabling the synthesis of a diverse range of 2-iminothiazolines bearing –SCN functional groups in good to excellent yields. Key advantages of this transition-metal free approach include a broad substrate scope, high functional group tolerance, mild reaction conditions, excellent product yields, scalability, and synthetic versatility. Mechanistic investigations suggest an ionic pathway for this transformation.