Cycloadditionsreaktionen im System 2-Isocyanato-4,4,5,5-tetramethyl-1,3,2-dioxaphospholan/1,1,1,5,5,5-Hexafluor-4-trimethylsiloxy-3-penten-2-on

Cycloaddition Reactions in the System 2-Isocyanato-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane/1,1,1,5,5,5-Hexafluor-4-trimethylsiloxy-3-pentene-2-one The two title compounds react to give in a (3+2) cycloaddition the spiro iminophosphoran 3 and its dimer 4 , respectively. The (2+2) cycloaddition of hexafluoracetone and 3 yields the oxazaphosphetane 5 , which decomposes rapidely into the Staudinger product 6 . The hydrolytical cleavage of the trimethylsilyl group furnishes the tricyclic phosphorane 7 . The ³J_PH coupling in 3 is surprisingly large (51.6 Hz).