Reactions of dipivaloylketene dimer with nucleophiles: new access to the 2, 6,9-trioxabicyclo(3.3.1)nona-3,7-diene ring system (bridged bis-dioxines)

A study was made on the preparative and mechanistic aspects of the formation of simple mono- and bifunctionalized trioxabicyclononadienes. The methods entailed the addition of nucleophiles to alpha-oxoketene 5 following a multistep reaction sequence. The results indicated the viability of the methods which permit the synthesis of several varieties of mono- and bifunctionalized derivatives as opposed to previous approaches which showed limited synthetic value.