Cycloaddition. -Significant amounts (20-45% NMR) of undesired regioisomers are also generated in some cases. -(MORI, A.; ARAKI, T.; MIYAUCHI, Y.; NOGUCHI, K.; TANAKA*, K.; Eur.

Complementary theoretical and experimental studies of the consecutive steps of superacid catalyzed polyhydroxyalkylation reactions have been carried out. Calculations for the superacid catalyzed polyhydroxyalkylation of trifluoroacetone and trifluoroacetophenone with aromatic hydrocarbons explained a number of experimental facts within a single theoretical framework of monoprotonation. The principal factors affecting kinetics of superacid mediated hydroxyalkylation were shown to be as follows: (i) the acidity of the superacid affecting protonation energy of carbonyl components; (ii) the electrophilicity of carbonyl components; and (iii) the nucleophilicity of aromatic components. The modification of those factors allows for tuning of the reactivity of carbonyl and aromatic components; thereby, reaction kinetics are controlled. The conclusions were confirmed by the experiments. Theoretically predicted stoichiometrically imbalanced polymerizations of trifluoroacetone, trifluoroacetophenone, octafluoroacetophenone, and isatin with nonactivated, aromatic hydrocarbons gave high-molecular-weight polymers with a very small excess of the carbonyl compound. The main reasons contributing to the polymerization accelerations were found to be an increase of the first, rate-determining step reaction, and a high efficiency of the superacid catalyzed polyhydroxyalkylations. The present work has thus opened a new route to preparations of polymers of linear, hyperbranched, or hybrid (e.g., linear−hyperbranched) architecture by operating on structural parameters and reaction conditions.

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A novel series of linear, high-molecular-weight polymers was synthesized by one-pot, superacidcatalyzed reaction of pentafluorobenzaldehyde (PFBA) (1) with nonactivated aromatic hydrocarbons: biphenyl, diphenyl ether, p-terphenyl, 4,4′-diphenoxybenzophenone, and 1,3-bis-and 1,4-bis(4′-phenoxybenzoyl)benzenes. The reactions were performed at room temperature in the Brønsted superacid trifluoromethanesulfonic acid (CF 3 SO 3 H, TFSA) and in a mixture of TFSA with methylene chloride. The polymer-forming reaction was highly dependent upon the acidity of the reaction medium, as judged from the molecular weights of the polymers obtained. A possible reaction mechanism is suggested. The polymers obtained were soluble in the common organic solvents, and flexible transparent films could be cast from the solutions. 1 H and 13 C NMR analyses of the polymers synthesized revealed their linear structure. The pendent pentafluorophenyl groups react regioselectively with nucleophiles under basic conditions in polar, aprotic solvents. Side-chain-type sulfonated polymers were obtained from reaction with sodium 4-hydroxybenzenesulfonate.