title: Radical O→C transposition: a metal-free process for conversion of phenols into benzoates and benzamides.
abstract: We report a metal-free procedure for transformation of phenols into esters and amides of benzoic acids via a new radical cascade. Diaryl thiocarbonates and thiocarbamates, available in a single high-yielding step from phenols, selectively add silyl radicals at the sulfur atom of the C═S moiety. This addition step, analogous to the first step of the Barton-McCombie reaction, produces a carbon radical which undergoes 1,2 O→C transposition through an O-neophyl rearrangement. The usually unfavorable equilibrium in the reversible rearrangement step is shifted forward via a highly exothermic C-S bond scission in the O-centered radical, which furnishes the final benzoic ester or benzamide product. The metal-free preparation of benzoic acid derivatives from phenols provides a potentially useful alternative to metal-catalyzed carbonylation of aryl triflates.
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, USA.
authors.forename: Abdulkader
authors.initials: A
authors.lastname: Baroudi
authors.forename: Jeremiah
authors.initials: J
authors.lastname: Alicea
authors.forename: Phillip
authors.initials: P
authors.lastname: Flack
authors.forename: Jason
authors.initials: J
authors.lastname: Kirincich
authors.forename: Igor V
authors.initials: IV
authors.lastname: Alabugin