Selective activation of diol groups by a borinic acid catalyst enables the synthesis of strictly linear polyesters from glycerol, a trifunctional monomer.

A new protocol for the reductive deoxygenation of primary alcohols was explored. This photomediated method combines a novel approach to bromination of alcohols merged with the powerful reducing capability of [Au 2 (dppm) 2 ]Cl 2

A new class of sugar-derived polyesters has been synthesized, using organoboron-catalyzed acylation to generate linear macromolecules having pyranoside units enchained with a uniform 3,6-connectivity. The method provides access to welldefined polymers bearing pendant hydroxyl groups, from commercially available diacid chlorides and readily accessible pyranoside feedstocks. Variation of the configuration of the pyranoside (α-manno, α-galacto, or β-galacto) and the identity of the aglycon has been conducted, enabling studies of structure− property relationships. Flexible, long-chain substituents at the anomeric position behave as intrinsic plasticizers, affording decreased glass-transition temperatures (T g ) relative to their short-chain counterparts. The T g values of this family of polymers were found to vary from −3 to 164 °C. Enzymatic degradation and cytotoxicity studies in vitro suggested that the pyranoside-derived polyesters are slow-degrading, cytocompatible materials. After being subjected to urethane cross-linking, the polymers were studied by dynamic mechanical analysis and tensile testing, revealing the impact of stereochemistry and aglycon structure on the elastic and complex moduli, damping, and elongation at failure. The presence of hydrogen-bond-donating OH groups also conferred self-healing behavior to one of the linear polymers. This work demonstrates how organoboron-catalyzed, site-selective activation of OH groups can be employed to generate well-defined, carbohydrate-derived polymers.

Light-Mediated Deoxygenation of Alcohols with a Dimeric Gold Catalyst. -A new protocol for the photolytic bromination of primary alcohols using CBr 4 and DMF is developed. Furthermore, a one-pot sequential bromination/gold-catalyzed reduction allows the deoxygenation of alcohols (VII). Substrates (IX) and (XI) undergo deoxygenation/cyclization to form piperidine and pyrrolidine derivatives. -(MCCALLUM, T.; SLAVKO, E.; MORIN, M.; BARRIAULT*, L.; Eur. J. Org. Chem. 2015, 1, 81-85, http://dx.doi.org/10.1002/ejoc.201403351 ; Dep. Chem., Univ. Ottawa, Ottawa, Ont. K1N 6N5, Can.; Eng.) -Mais 19-052