title: Regioselectivity and mechanism of dihalocarbene addition to benzocyclopropene.
abstract: Dihalocarbenes add regioselectively to aryl-substituted benzocyclopropenes to produce dihalobenzocyclobutenes. The regioselectivity of addition is not due to steric effects but depends on the electronic donor or acceptor ability of the substituent. B3LYP/6-31G* calculations show preferential :CCl2 addition to substituted benzocyclopropene through electrophilic attack on the benzocyclopropene pi-system (Ea = 1.1-2.4 kcal/mol) rather than C-C sigma-bond insertion into the cyclopropenyl moiety (Ea = 5-24 kcal/mol). pi-Addition proceeds regioselectively through a single transition state to xylylene intermediates or directly to benzocyclobutene products.
authors.affiliation: Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, USA.
authors.forename: Marina
authors.initials: M
authors.lastname: Khrapunovich
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Zelenova
authors.forename: Lillian
authors.initials: L
authors.lastname: Seu
authors.forename: Alexis N
authors.initials: AN
authors.lastname: Sabo
authors.forename: Aidan
authors.initials: A
authors.lastname: Flaherty
authors.forename: Dina C
authors.initials: DC
authors.lastname: Merrer