Syndioselective Polymerization of a BN Aromatic Vinyl Monomer

A new synthetic platform accessing stereoregular polar polyolefins is introduced. We showcase the stability of aromatic azaborine derivatives by demonstrating the syndioselective polymerization of BN 2-vinylnaphthalene (BN2VN) by a monocyclopentadienyl titanium complex. Homogeneous early transition metal catalysts are well-established systems for the synthesis of highly stereoregular syndiotactic polystyrene (sPS), but the oxophilic nature of these complexes results in catalyst decomposition with polar monomers. BN2VN's compatibility with coordination polymerization, and its ability to intercept the mechanism of styrene polymerization, is attributed to its aromaticity. Stereoretentive postpolymerization oxidation of the organoborane side chain generates syndiotactic poly(vinyl alcohol) (sPVA), an example of PBN2VN's potential for diverse postfunctionalization.