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Synthesis and Polymerization of Optically Active N ‐Propargylphosphonamidates: A Novel Helical Polymer Carrying a P‐Chiral Center
Author(s) -
Yue Dongmei,
Fujii Toru,
Terada Kayo,
Tabei Junichi,
Shiotsuki Masashi,
Sanda Fumio,
Masuda Toshio
Publication year - 2006
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200600347
Subject(s) - polyacetylene , polymerization , diastereomer , polymer , polymer chemistry , cotton effect , chemistry , materials science , stereochemistry , circular dichroism , organic chemistry
Summary: A diastereomeric pair of novel N ‐propargylphosphonamidates, HCCCH 2 NHP(O)(CH 3 )O‐ L ‐menthyl was synthesized by the successive condensations of methylphosphonic dichloride with L ‐menthol and propargylamine. The ( R )‐P‐isomer ( 1a ) was isolated, and the absolute configuration was determined by XRD. Polymerization of 1a , and a mixture of 1a and ( S )‐P‐isomer ( 1b ) was carried out with a zwitterionic Rh complex as a catalyst. cis ‐Stereoregular polymers with number‐average molecular weights of 5 600–9 800 were obtained in good yields. Poly( 1a ) and poly( 1a 29 ‐ co ‐ 1b 71 ) exhibited large specific rotations (+408 and −146°), and intense Cotton effects ([ θ ] = +2.25 and −0.9 × 10 4 deg · cm 2 · dmol −1 ) based on the conjugated polyacetylene backbone around 325 nm in CHCl 3 , indicating that these polymers have helical structures, whose predominant helical senses are opposite.Polymerization of N ‐propargylphosphonamidate.