Stereochemistry of the photoinduced and Michael addition of methanol to seven-and eight-membered 2-cycloalkenones. The effect of methyl substituents

H Hart, BL Chen, M Jeffares

Index: Hart,H. et al. Journal of Organic Chemistry, 1979 , vol. 44, # 15 p. 2722 - 2726

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Citation Number: 33

Abstract

Irradiation of 2-methyl-2-cycloheptenone (4) or 2-methyl-2-cyclooctenone (6) in methanol gave only the corresponding cis-3-methoxy-2-methylcycloalkanones 5c and 7c, respectively, rationalized as a consequence of syn methanol addition to the trans enones. The isotope effect (CH, OH/CH, OD) for 4 was 2.0, appreciably less than the previously observed value for 2-cycloheptenone, suggesting that the 2-methyl substituent destabilizes the trans ...