On the mechanism of regioselectivity control by donor substituents on electrophilic alkenes: applications to quinone cycloadditionregioselectivity
1981; Elsevier BV; Volume: 22; Issue: 22 Linguagem: Inglês
10.1016/s0040-4039(01)93273-3
ISSN1873-3581
AutoresI.‐M. TEGMO‐LARSSON, Melvin D. Rozeboom, Nelson G. Rondan, K. N. Houk,
Tópico(s)Oxidative Organic Chemistry Reactions
ResumoDonor substitution on alkenes slightly increases the LUMO coefficient at the site of substitution. However, nucleophiles preferentially attack the unsubstituted terminus of the alkene due to direct repulsive interactions between the nucleophile and the substituent. Secondary orbital interactions make the terminus remote from the site of substitution the most electrophilic. LUMO coefficients, or equivalent spectroscopic measures, esr hyperfine coupling in the esr spectra of radical anions, are appropriate for prediction of reactivities of unsubstituted positions but not substituted ones.
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