Theoretical insights into Rh-catalyzed hydroamidation: Mechanism and chemoselectivity.

• Establishing a complete mechanism for Rh-catalyzed hydroamidation of unactivated alkenes with methyl dioxazolone. • Investigating into chemoselectivity: hydroamidation vs. C C bond aziridination and hydroamidation vs. C(sp2/sp3) H bond amidations. • The preference of singlet and triplet C H bond insertions have been clarified. • Unravelling the origins of high chemoselectivity toward hydroamidation. Rh-catalyzed hydroamidation of unactivated alkenes were investigated by a density functional theory study. The catalytic cycle proceeds through β-H elimination, alkene addition, CO 2 extrusion, nitrene migratory insertion and protodemetalation. CO 2 extrusion is the rate-determining step for the overall reaction. More importantly, the hydroamidation-to-aziridination and hydroamidation-to-amidation chemoselectivities have been investigated and the origins of impossibilities of C C bond aziridination and C(sp2/sp3) H bond amidations have been elucidated. The Rh-nitrene group is more inclined to insert Rh C bond rather than C C and C(sp2/sp3) H bonds to form the new C N bond of hydroamidation products. These calculation results provide valuable information for further selective synthesis of amides. The hydroamidation-to-aziridination and hydroamidation-to-amidation chemoselectivities have been investigated, and the origins of these high chemoselectivities have been elucidated. [Display omitted] [ABSTRACT FROM AUTHOR]