Mechanism and Origins of Regiochemical Control in Rh(III)-Catalyzed Oxidative C–H Alkenylation and Coupling Sequence of Unprotected 1‑Naphthylamines with α,β-Unsaturated Esters

The
rhodium­(III)-catalyzed oxidative C–H alkenylation and
coupling sequence of unprotected 1-naphthylamines with α,β-unsaturated
esters, which were recently developed by our group, provide an efficient
strategy for highly regiocontrolled cyclization and a route to producing
biologically important alkylidene-1,2-dihydrobenzo­[cd]­indole scaffolds. The selectivity of this reaction was studied using
density functional theory calculations. A detailed computational study
of the reaction mechanism indicated that the regiochemistry of the
reaction is controlled by several steps: (i) peri-selective C–H activation, (ii) linear-selective migratory
insertion, and (iii) hydrogen-bonding-assisted β-hydride elimination,
and the preferred pathway based on calculations is in agreement with
the experimentally observed cyclization products.