Polymerization of Aromatic Aldehydes. VII. Cyclopolymerization of o-FormylphenylacetaIdehyde and Formation of a Cyclic Trimer

Abstract

Polymerization of o-formylphenylacetaldehyde was carried out with various catalysts. The polymer obtained below −60°C with BF3OEt2 catalyst was soluble in common organic solvents and was confirmed as a cyclopolymer composed of 6-membered cyclized units. The cationic cyclization step in the cyclopolymerization of o-formylphenylacetaldehyde was inferred to proceed through a intermediate or concerted scheme similar to those proposed for the cationic propagation of o-phthalalde-hyde.On the other hand, under cationic polymerization conditions over −40°C o-formylphenylacetaldehyde gave a cyclic trimer (mp 284–285°C) possessing fused ring ether, which had no aldehyde group. Interestingly, the cyclic trimer was also produced from the polymer by treatment with BF3OEt2 in methylene dichloride.Cyclopolymers of o-formylphenylacetaldehyde were also obtained with Ziegler catalyst at 0 and −78°C, and with t-BuOLi catalyst at −78°C.