Scope and limitations of ruthenium-catalyzed metathesis of simple polymer-bound alkenes

Synthetic procedures for the preparation of two types of functional resin a re described, both based on 2% cross-linked polystyrene with a high density (> 60%) of side-chains and terminated by a primary alcohol. In the first c ase the C-11 side-chain is linked to the polymer through a sulfide, and in the second an ether linkage is employed to incorporate a (CH2CH2O)(4) unit. In both cases the resins have C-13 NMR spectra that are informative in the chain terminus region without special operating conditions. Model intermol ecular metathesis reactions were carried out on allylcarbamic acid tert-but yl ester and various alkenes with Grubbs' catalyst. On the basis of these e xperiments, gel-phase metathesis was successfully demonstrated between a po lymer-bound allyl ether and simple symmetrical disubstituted alkenes, monit oring the extent of reaction by C-13 NMR. These reactions did not go to com pletion even with recycling and some evidence for competing interchain meta thesis is presented, based on the increased broadening and reduced mobility of the ensuing polymer.