Novel Optically Active Polyacetylenes: Synthesis and Helical Conformation of L ‐Lysine‐Dendronized Poly(phenylacetylene)

Summary: The novel chiral phenylacetylene ( 1 ) functionalized with an L ‐lysine‐based dendritic peptide was synthesized and polymerized with Rh catalysts to afford the corresponding polymer [poly( 1 )] with moderate molecular weights in good yields. Poly( 1 ) was soluble in common organic solvents including DMF, THF, CHCl 3 , AcOEt, and MeOH. The polarimetric and CD spectroscopic data indicate that poly( 1 ) exists in a helical structure with predominantly one‐handed screw sense in THF and CHCl 3 . Poly( 1 ) also assumes a helical structure in the solid state. This helical structure can be tuned by heat in CHCl 3 or by the addition of a protic solvent to CHCl 3 solutions.Synthesis of chiral poly(phenylacetylene) bearing a L ‐lysine‐based dendritic peptide in the side chain.