title: Unexpected migration and oxidative cyclization of substituted 2-acetophenone triflates under basic conditions: synthetic and mechanistic insights.
abstract: Oxidative ring closure of alkyl-substituted 2-hydroxyacetophenone trifluoromethanesulfonate esters (triflates) occurs upon exposure to base in anaerobic DMF at 20-90 degrees C. Alkyl substitution is required for ring closure. A migrated enol triflate product forms at lower temperature in high yield via migration of the trifluoromethanesulfonate in the unsubstituted and monoalkyl-substituted cases. The alkyl-substituted enol triflates also enter into the benzofuran-3-one ring-forming process under thermal cyclization conditions. Potential mechanistic pathways are evaluated.
authors.affiliation: Pfizer Global Research and Development, Groton Laboratories, Pfizer Inc., Groton, Connecticut 06340, USA. coejw@groton.pfizer.com
authors.forename: Jotham W
authors.initials: JW
authors.lastname: Coe
authors.forename: Krista E
authors.initials: KE
authors.lastname: Bianco
authors.forename: Brian P
authors.initials: BP
authors.lastname: Boscoe
authors.forename: Paige R
authors.initials: PR
authors.lastname: Brooks
authors.forename: Eric D
authors.initials: ED
authors.lastname: Cox
authors.forename: Michael G
authors.initials: MG
authors.lastname: Vetelino