Selenium-Mediated Conversion of Alkynes into α-Dicarbonyl Compounds

Article abstract of DOI:10.1021/jo00014a038

The reaction of terminal and internal alkynes with diphenyl diselenide and ammonium peroxydisulfate in methanol proceeds smoothly to give α-keto acetals and α-keto ketals, respectively.This one-pot procedure is suggested to proceed through the initial formation of phenylselenenyl sulfate, a strong electrophilic reagent which effects the methoxyselenenylation of the alkynes.The addition products thus formed suffer methoxydeselenenylation giving the observed products and regenerating the phenylselenenylating agent.In some cases the reaction can be carried out using only catalytic amounts of diphenyl diselenide.The same reaction carried out in the presence of water or of ethylene glycol gives the unprotected or the diprotected α-dicarbonyl compounds, respectively.