Synthesis and Polymerization of Optically Active N-Propargylphosphonamidates: A Novel Helical Polymer Carrying a P-Chiral Center

✍ Scribed by Dongmei Yue; Toru Fujii; Kayo Terada; Junichi Tabei; Masashi Shiotsuki; Fumio Sanda; Toshio Masuda

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 215 KB
• Volume: 27
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/marc.200600347

✦ Synopsis

Abstract

Summary: A diastereomeric pair of novel N‐propargylphosphonamidates, HCCCH~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.

magnified imagePolymerization of N‐propargylphosphonamidate.