Selective ring-rearrangement or ring-closing metathesis of bicyclo[3.2.1]octenes

Explored was the competitive ring-closing metathesis vs . ring-rearrangement metathesis of bicyclo[3.2.1]octenes prepared by a simple and convergent synthesis from bicyclic alkylidenemalono-nitriles and allylic electrophiles. It was uncovered that ring-closing metathesis occurs exclusively on the tetraene-variant, yielding unique, stereochemically and functionally rich polycyclic bridged frameworks, whereas the reduced version (a triene) undergoes ring-rearrangement metathesis to 5 - 6 - 5 fused ring systems resembling the isoryanodane core. Explored was the competitive ring-closing metathesis vs . ring-rearrangement metathesis of bicyclo[3.2.1]octenes prepared by a simple and convergent synthesis from bicyclic alkylidenemalononitriles and allylic electrophiles.