Synthesis of Phosphet-2-one Derivatives via Phosphinidene Transfer to Cyclopropenones

Abstract

We report the first synthesis and structural characterization of free, uncomplexed phosphet-2-ones. These unsaturated four-membered phosphacycles were prepared by phosphinidene transfer from dibenzo-7-phosphanorbornadiene compounds, RP A ( A = C 14 H 10, anthracene), to cyclopropenones in yields of up to 89%. Theoretical studies suggest that the reaction proceeds through ketene-ylide and ketene-phosphaalkene intermediates. Further transformations of the phosphet-2-ones led to the isolation of more phosphet-2-ones and 1,2-dihydrophosphetes, including two furanone derivatives which are postulated to be produced by intramolecular phosphine-catalyzed [3 + 2] annulations.

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