The ethyl oxazole-4-carboxylate was directly and regioselectively alkenylated, benzylated and alkylated with alkenyl-, benzyl-, allyl- and alkylhalides in the presence of catalytic amounts of palladiumacetate with caesium carbonate using Buchwald's JohnPhos ligand.
Rhodium-catalyzed heterocycloaddition route to 1,3-oxazoles as building blocks in natural products synthesis
作者:Richard D. Connell、Mark Tebbe、Anthony R. Gangloff、Paul Helquist、Björn Åkermark
DOI:10.1016/s0040-4020(01)87261-6
日期:——
Rhodium(II) acetate serves as a catalyst for the heterocycloaddition reaction of diazodicarbonyl compounds with nitriles to give functionalized 1,3-oxazole derivatives in a simple one-step procedure. In particular, dimethyl diazomalonate undergoes this reaction to give 2-aryl-, 2-alkenyl-, or 2-alkyl-4-carbomethoxy-5-methoxy-1,3-oxazoles, and ethyl formyldiazoacetate (diazomalonate half-ester half-aldehyde)