Gold-catalyzed highly regioselective oxidation of C-C triple bonds without acid additives: propargyl moieties as masked α,β-unsaturated carbonyls.
Biao Lu, Chaoqun Li, Liming Zhang
Index: J. Am. Chem. Soc. 132 , 14070-14072, (2010)
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Abstract
Gold-catalyzed intermolecular oxidations of internal alkynes have been achieved with high regioselectivities using 8-alkylquinoline N-oxides as oxidants and in the absence of acid additives. Synthetically versatile α,β-unsaturated carbonyls are obtained in good to excellent yields and with excellent E-selectivities. A range of functional groups such as THP, MOMO, N(3), OTBS, and N-Boc are tolerated. This reaction allows α,β-unsaturated carbonyls to be masked as propargyl moieties, thus offering a practical solution to compatibility issues with these functional groups likely encountered in syntheses of complex structures.