ADDITIONS OF CARBENIUM IONS TO NONCONJUGATED DIENES - THE RETARDING (-I)-EFFECT OF THE 2ND DOUBLE-BOND

[摘要] Kinetics for the addition of the p-methoxybenzhydryl cation (AnPhCH+, 10) towards nonconjugated dienes 11 [H2C = C(CH3)-(CH2)n-C(CH3) = CH2] have been determined in CH2Cl2 at -30-degrees to -70-degrees-C. Reactivity increases with increasing number of methylene groups separating the two double bonds. For n = 4, reactivity reaches the value for saturated alkyl substituents, and nucleophilic assistance of the second double bond is never observed.

[发布日期] 1991-01-07