title: Site selectivity switch in Lewis acid catalysis. Mechanism and kinetic simulation of skeletal rearrangement of cyclobutene-fused homoquinones.
abstract: [reactions: see text] We investigated the site selectivity switch in BF3-catalyzed dual skeletal rearrangements of cyclobutene-fused diarylhomobenzoquinones by changing the stoichiometric amount of acid concentration. From the lower to the higher equivalency of BF3 x Et2O, the branching product ratios (path A/path B) obeyed nonlinear sigmoid curves against the equivalency of BF3 x Et2O. The observed selectivity profiles were simulated to elucidate factors that govern thermodynamic aspects (binding affinity K of each carbonyl function with acid) and kinetic aspects (rate constants k for the cyclobutene-ring cleavage).
authors.affiliation: Division of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Kokubo
authors.forename: Takuya
authors.initials: T
authors.lastname: Koizumi
authors.forename: Kenji
authors.initials: K
authors.lastname: Harada
authors.forename: Eiko
authors.initials: E
authors.lastname: Mochizuki
authors.forename: Takumi
authors.initials: T
authors.lastname: Oshima