Cyclopolymerization, 30. Design of an Unconjugated Diene with High Polymerizability Using Functional Groups with No Homopolymerization Tendency, and Synthesis of Completely Cyclized Polymers therefrom: Radical Polymerizations of N-Phenyl-N-2-(methoxycarbonyl)allyl(meth)acrylamide

Abstract

Cyclopolymerizabilities of N-phenyl-N-2-(methoxycarbonyl)allylmethacrylamide (1 a) and N-phenyl-N-–2-(methoxycarbonyl)allylacrylamide (1 b) were compared to see the validity of the concept proposed previously for the design of 1,6-dienes with both a high cyclization tendency and a high polymerizability. It states that the use of functional groups with a higher conjugative nature together with a no homopolymerization tendency is essential for the purpose. Of the four monofunctional counterparts of these dienes, only N-phenyl-N-2-(methoxycarbonyl)propylacrylamide, one of the monoene counterparts of 1 b, is assumed to have high homopolymerization tendency, judging from the polymerizabilities of compounds with similar structure. α-Substituted acryloyl groups of 1 a and 1 b have higher conjugative natures. This indicates that both the dienes have high polymerizability but their cyclization tendency is essentially different; i. e., 1 a yields highly cyclized polymers, while polymers with lower degrees of cyclization are obtained from 1 b. The results obtained were in good accordance with this consideration. Repeat cyclic units of poly(1 a) and poly(1 b) consist mainly of five-membered rings. Both the double bonds of 1 b were pendant unsaturations in poly(1 b). Mechanism of the polymerizations was discussed based on the results obtained.