Reaction of 3,3-dialkyl-6-trifluoromethyl-2,3-dihydro-4-pyrones with alkyl mercaptoacetates. Synthesis of derivatives of 2-oxa-7-thiabicyclo[3.2.1]octane

A Novel Redox Reaction between 8-Aza-5,7-dimethyl-2-trifluoromethylchromone and Alkyl Mercaptoacetates. Facile Synthesis of CF3-Containing 2-Pyridone Derivatives

“…The mechanism for the redox formation of coumarins 2 is not obvious, but it is most likely that, as in the cases with 3,3-dialkyl-6-trifluoromethyl-2,3-dihydro-4-pyrones and 7-polyfluoroalkylnorkhellins, in which esters of thioglycolic acid act as S , C -dinucleophiles, the reaction initially gives benzo derivatives of 2-oxa-7-thiabicyclo[3.2.1]octane 3 , which undergo the reductive ring opening to esters 4 under the action of ethyl mercaptoacetate. The latter compound is oxidized to diethyl 3,4-dithiadipate and further two intramolecular cyclizations of the intermediate ester 4 give dihydrothienocoumarins 2 .…”

A Novel Redox Reaction between 8-Aza-5,7-dimethyl-2-trifluoromethylchromone and Alkyl Mercaptoacetates

“…The mechanism for the redox formation of coumarins 2 is not obvious, but it is most likely that, as in the cases with 3,3-dialkyl-6-trifluoromethyl-2,3-dihydro-4-pyrones and 7-polyfluoroalkylnorkhellins, the reaction initially gives benzo derivatives of 2-oxa-7-thiabicyclo[3.2.1]octane 3 , which undergo the reductive ring-opening to esters 4 under the action of ethyl mercaptoacetate (Scheme ). Unfortunately, we were unable to isolate any intermediates in the transformation 1 → 2 .…”