Tandem Wolff rearrangement-'tert-amino effect' sequence: Synthesis of 2-oxoindolinium enolate and 1H-2-benzopyrane derivatives

Article abstract of DOI:10.1016/0040-4039(95)01636-V

The thermal decomposition of dimethyl 1-diazo-2-oxo-(2-N,N-disubstituted aminophenyl)ethylphosphonates 1 gave rise to 2-oxoindolinium enolates 3 resulting from a Wolff rearrangement followed by attack of the nitrogen atom on the intermediate ketene moiety