7175-94-2Relevant articles and documents
Radical OfC transposition: A metal-free process for conversion of phenols into benzoates and benzamides
Baroudi, Abdulkader,Alicea, Jeremiah,Flack, Phillip,Kirincich, Jason,Alabugin, Igor V.
, p. 1521 - 1537 (2011/06/11)
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 CdS moiety. This addition step, analogous to the first step of the Barton-McCombie reaction, produces a carbon radical which undergoes 1,2 OfC 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.
Metal-free transformation of phenols into substituted benzamides: A highly selective radical 1,2-O→C transposition in O-aryl-N-phenylthiocarbamates
Baroudi, Abdulkader,Flack, Phillip,Alabugin, Igor V.
supporting information; experimental part, p. 12316 - 12320 (2010/12/29)
Radical merry-go-round: A highly efficient metal-free transformation of phenols into benzamides is designed through one-step conversion of phenols to aryl thiocarbamates and a subsequent radical addition/rearrangement/ fragmentation cascade. Computational analysis fully rationalizes the experimentally observed selectivity. Despite the possible competition from N-C fragmentation and N-neophyl rearrangement, the transformation exclusively follows the most kinetically and thermodynamically favored O-neophyl rearrangement path.
