Novel optically active substituted acetylenes HC CCH₂CR¹(CO₂CH₃)NHR² [(S)-/(R)-1: R¹ = H, R² = Boc, (S)-2: R¹ = CH₃, R² = Boc, (S)-3: R¹ = H, R² = Fmoc, (S)-4: R¹ = CH₃, R² = Fmoc (Boc = tert-butoxycarbonyl, Fmoc = 9-fluorenylmethoxycarbonyl)] were synthesized from α-propargylglycine and α-propargylalanine, and polymerized with a rhodium catalyst to provide the polymers with number-average molecular weights of 2400–38,900 in good yields. Polarimetric, circular dichroism (CD), and UV–vis spectroscopic analyses indicated that poly[(S)-1], poly[(R)-1], and poly[(S)-4] formed predominantly one-handed helical structures both in polar and nonpolar solvents. Poly[(S)-1a] carrying unprotected carboxy groups was obtained by alkaline hydrolysis of poly[(S)-1], and poly[(S)-4b] carrying unprotected amino groups was obtained by removal of Fmoc groups of poly[(S)-4] using piperidine. Poly[(S)-1a] and poly[(S)-4b] also exhibited clear CD signals, which were different from those of the precursors, poly[(S)-1] and poly[(S)-4]. The solution-state IR measurement revealed the presence of intramolecular hydrogen bonding between the carbamate groups of poly[(S)-1] and poly[(S)-1a]. The plus CD signal of poly[(S)-1a] turned into minus one on addition of alkali hydroxides and tetrabutylammonium fluoride, accompanying the red-shift of λ_max. The degree of λ_max shift became large as the size of cation of the additive. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

A series of [(dppf)PdBr(R)]-type complexes (dppf=1,1′-bis(diphenylphosphino)ferrocene; R=p-cyanophenyl (1 a), o-hydroxymethylphenyl (1 b), and triphenylvinyl (1 c)), in combination with silver trifluoromethanesulfonate (AgOTf), were demonstrated to be active for the polymerization of monosubstituted polar acetylene monomers HCCCONHC₄H₉ (2), HCCCO₂C₈H₁₇ (3), HCCCH₂OCONHC₆H₁₃ (4), HCCCH₂OCO₂C₆H₁₃ (5), and HCCCH(CH₃)OH (6). The yields and molecular weights of the polymers depended on the combination of the Pd catalyst and monomer that was employed. Matrix-assisted laser-desorption/ionization–time of flight (MALDI-TOF) mass spectrometric analysis indicated the formation of polymers that contained the “R” and “H” groups at the chain ends. IR spectroscopic analysis supported the R-end-functionalization of the polymers. NMR spectroscopy and MS identified the presence of species that were formed by single, double, and triple insertion of the monomers into the Pd-C₆H₄-p-CN bond, thereby giving solid evidence for an insertion mechanism for the present system. Density functional theory (DFT) calculations suggested the preference for 1,2-insertion of the monomer compared to 2,1-insertion.