La. Paquette et al., A convenient method for removing all highly-colored byproducts generated during olefin metathesis reactions, ORG LETT, 2(9), 2000, pp. 1259-1261
Addition of a very modest amount of lead tetraacetate (1.50 equiv relative
to the amount of Grubbs catalyst) to ring-closing metathesis reaction mixtu
res effectively removes all colored ruthenium and phosphine impurities to d
eliver colorless reaction products.