Journal of the American Chemical Society

Stereopopulation control. VII. Rate enhancement in the lactonization of 3-(o-hydroxyphenyl) propionic acids: dependence on the size of aromatic ring substituents

MM King, LA Cohen

Index: King, Michael M.; Cohen, Louis A. Journal of the American Chemical Society, 1983 , vol. 105, # 9 p. 2752 - 2760

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Citation Number: 38

Abstract

Abstract: A series of 4, 4-dimethyl-6-hydroxyhydrocoumarins was synthesized with various combinations of methyl and halogen groups at C-5 and C-7. The 5, 7-difluoro compound was obtained by condensation of difluorohydrcquinone with dimethylacrylic ester. Controlled chlorination of the parent phenolic lactone provided the 5-and 7-chloro isomers, in addition to the 5, 7-dichloro product. On the other hand, bromination gave both the 5, 7-dibromo ...