The palladium insertion polymerization catalysts (bipy)Pd(CH3)L+OTf- have been found to mediate a second class of polymerization reaction:  the ring-opening polymerization of heterocycles. Unlike traditional cationic ring-opening processes, this polymerization is found to proceed via an unusual series of metal-based reactions, including novel steps which allow the coupling of insertion monomers (CO and norbornene) with ring-opened polymers.

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Furan derivativesFuran derivatives R 0060 Catalytic Enantioselective Homoaldol Reactions Using Binol Titanium(IV) Fluoride Catalysts. -A combined chiral Ti(IV)-catalyst prepared from TiF4, (R)-BINOL and allyltrimethylsilane is used for the homoaldol reaction of the cyclopropane (I) and aldehydes (II). After acid-promoted lactonization, the products (III) are obtained with moderate e.e. -(BURKE, E. D.; LIM, N. K.; GLEASON*, J. L.; Synlett 2003, 3, 390-392; Dep. Chem., McGill Univ., Montreal, Que. H3A 2K6, Can.; Eng.) -Mais 23-096

Titanium (IV) fluoride catalysts, prepared by the combination of (R)-2,2′-binaphthol and TiF 4 , are effective for promoting the homoaldol addition of 1-ethoxy-1-(trimethylsilyloxy)cyclopropane to aldehydes. The reactions proceed with ee's of up to 72% and are effective with a range of aldehyde substrates. The reactions show greatly improved enantioselectivity when compared to those catalyzed by titanium(IV) triflates. The increase in selectivity is presumed to result from the elimination of deleterious silicon cocatalysis.