A Modular Synthesis of Teraryl‐Based α‐Helix Mimetics,Part 1: Synthesis of Core Fragments with Two Electronically Differentiated Leaving Groups

Teraryl‐based α‐helix mimetics have proven to be useful compounds for the inhibition of protein–protein interactions (PPI). We have developed a modular and flexible approach for the synthesis of teraryl‐based α‐helix mimetics. Central to our strategy is the use of a benzene core unit featuring two leaving groups of differentiated reactivity in the Pd‐catalyzed cross‐coupling used for terphenyl assembly. With the halogen/diazonium route and the halogen/triflate route, two strategies have successfully been established. The synthesis of core building blocks with aliphatic (Ala, Val, Leu, Ile), aromatic (Phe), polar (Cys, Lys), hydrophilic (Ser, Gln), and acidic (Glu) amino acid side chains are reported.     

Synthesis and characterization of semicrystalline triblockcopolymers of isotactic polystyrene and polydimethylsiloxane

iPS‐b‐PDMS‐b‐iPS triblock copolymers were prepared by hydrosilylation of vinyl‐terminated isotactic polystyrenes (iPS) with α,ω‐bis(dimethylsilane)‐terminated poly(dimethylsiloxane)s (PDMS). As a function of the molecular weights of the two components, the triblock copolymer composition was varied between 9.0 and 98 wt % iPS. The resulting triblock copolymers remained soluble during block copolymer synthesis due to slow iPS crystallization in solution. At iPS content exceeding 31 wt %, the iPS crystallization was achieved by postpolymerization annealing and melt processing. The triblock copolymers melted above 200 °C with melting temperatures very similar to those of the corresponding iPS homopolymers. Nanostructure and microstructure formation of both amorphous and semicrystalline triblock copolymers were examined by means of light microscopy, atomic force microscopy, and TEM measurements. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011