Controlled ring-opening metathesis polymerization by molybdenum and tungsten alkylidene complexes

Article abstract of DOI:10.1016/0304-5102(88)85097-1

A new, convenient preparation of W(CH^tBu)(NAr)Cl₂(dme) involves treatment of W(NAr)(O^tBu)₂(CH₂²Bu)₂ with PCl₅ in dimethoxyethane as a final step. From it a variety of complexes of the type W(CH^tBu)(NAr)(OR)₂ can be prepared straightforwardly in high yield. Analogous complexes of the type Mo(CH^t-Bu)(NAr)(OR)₂ were also prepared. Complexes in which OR = O^tBu will not react with ordinary olefins, but will react with strained cyclic olefins such as norbornene (NBE) and cyclopentene to give living polymers from which the organic polymer can be cleaved by treatment with aldehydes.