PYRANDERIVATE DURCH -CYCLOADDITION ZWISCHEN α,β-UNGESAETTIGTEN CARBONYLVERBINDUNGEN UND PHOSPHACUMULENYLIDEN

Article abstract of DOI:10.1016/S0040-4039(01)80181-7

α,β-Unsaturated carbonyl compounds 1 and phosphacumulene ylides 2 undergo a <4+2>-cycloaddition with formation of pyran-substituted phosphoranes 3.Benzoic acid catalyzed Hofmann degradation of 3 yields the deeply coloured pyran derivatives 5.