Multi‐Pathway Consequent Chemoselectivities of CpRuCl(PPh 3 ) 2 /MeI‐Catalysed Norbornadiene Alkyne Cycloadditions

Chemoselectivities of five experimentally realised CpRuCl(PPh 3 ) 2 /MeI‐catalysed couplings of 7‐azabenzo‐norbornadienes with selected alkynes were successfully resolved from multiple reaction pathway models. Density functional theory calculations showed the following mechanistic succession to be energetically plausible: (1) CpRuI catalyst activation; (2) formation of crucial metallacyclopentene intermediate; (3) cyclobutene product ( P2 ) elimination (Δ G Rel(RDS) ≈11.9–17.6 kcal mol −1 ). Alternative formation of dihydrobenzoindole products ( P1 ) by isomerisation to azametalla‐cyclohexene followed by subsequent CpRuI release was much less favourable (Δ G Rel(RDS) ≈26.5–29.8 kcal mol −1 ). Emergent stereoselectivities were in close agreement with experimental results for reactions a , b , e . Consequent investigations employing dispersion corrections similarly support the empirical findings of P1 dominating in reactions c and d through P2 → P1 product transformations as being probable (Δ G ≈25.3–30.1 kcal mol −1 ).