Olefin metathesis (Grubbs)

Ruthenium-alkylidene catalysts exchange the alkylidene halves of two olefins: R₁CH=CHR₂ + R₃CH=CHR₄ ⇌ R₁CH=CHR₃ + R₂CH=CHR₄ (and related products). Proceeds through a metallacyclobutane intermediate (Chauvin mechanism). Enables…