Zum Cycloadditionsverhalten von bis(trifluormethyl)substituierten Nitril-yliden [1]. Positionsselektivität und Regiochemie bei Abfangreaktionen mit Heterokumulenen / Cycloaddition Behaviour of Bis(trifluoromethyl) Substituted Nitrile Ylides [1]. Site Selectivity and Regiochemistry of Trapping Reactions with Heterocumulenes

2,2,2-Trimethoxy-3,3-bis(trifluoromethyl)-2,2-dihydro-1,4,2-oxazaphosphol-4-enes on thermolysis undergo a 1,3-dipolar cycloreversion reaction with formation of bis(trifluoromethyl) substituted nitrile ylides and trimethyl phosphate. The nitrile ylides are trapped by N-sulfinyl aniline, phenyl isocyanate, phenyl isothiocyanate, diphenyl ketene, and carbon disulfide. Site selectivity and regiochemistry of the [3 + 2]cycloaddition reactions are described. The results are compared with those obtained from [3 + 2]cycloaddition reactions of nitrile imines, nitrile oxides, alkyl, and aryl substituted nitrile ylides with heterocumulenes.