Synthesis of Polymers Bearing a Chiral Backbone via Stereospecific Ionic Ring-Opening Polymerization of Chiral Donor-Acceptor Cyclopropanes.

The stereospecific ionic ring-opening polymerization of various donor-acceptor cyclopropanes is reported. The chiral cyclopropane monomers are readily prepared with established methodology and stereospecific polymerization is best conducted with a catalytic amount of MgBr serving as a Lewis acid and as an initiator. Polymers with molecular masses of up to 7800 g mol containing a stereocenter in every repeating unit are obtained and the substituents of the monomers can be readily varied to access a novel class of chiral polymers.

Intermolecular Heck Coupling with Hindered Alkenes Directed by Potassium Carboxylates.

Pd -catalyzed Mizoroki-Heck reactions traditionally exhibit poor reactivity with polysubstituted, unbiased alkenes. Intermolecular reactions with simple, all-carbon tetrasubstituted alkenes are unprecedented. Herein we report that pendant carboxylic acids, combined with bulky monophospine ligands on palladium, can direct the arylation of tri- and tetrasubstituted olefins.