SYNTHESIS AND REACTIONS OF TRIHALOMETHYL GROUP SUBSTITUTED ELECTRON-DEFICIENT OLEFINS.
AuthorHEDRICK, STEVEN THOMAS.
Electron donor-acceptor complexes.
Carbenes (Methylene compounds)
AdvisorHall, H. K.
MetadataShow full item record
PublisherThe University of Arizona.
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AbstractThe reactions of five trihalomethyl group substituted electron-deficient olefins with electron-rich olefins were studied in order to determine the effect of steric bulk upon the subsequent reactions of the tetramethylene intermediates initially formed. Reactions of β-trihalomethyl group substituted olefins yielded cyclobutane adducts, resulting from a gem dimethyl effect which accelerates the collapse of the tetramethylene intermediate. Reactions of α-trihalomethyl group substituted olefins gave both small molecule and polymeric products. Polymers were produced in reactions where steric interactions between the termini of the tetramethylene intermediates prevented ring formation. Ester substituted electron-deficient olefins reacted with electron-rich olefins to give both cyclobutane and 6-alkoxy-3,4-dihydro-2H-pyran derivatives. A transition from concerted to stepwise reaction was observed, resulting from steric hindrance in the transition state leading to [4+2] cycloaddition. Exploratory studies of ion-radical propagation and chain transfer in polymerization processes were also conducted. The acid catalyzed free radical polymerization of imines was attempted, along with chain transfer studies of zwitterion-radical intermediates.