Oximes ketenimines

The oxime 299 is silylated in the presence of catalytic amounts of TMSOTf 20 to 300, which affords, via the Beckmann fragmentation intermediate 301 and alkylation with allyltrimethylsilane 82, 66% of the seco nitrile 302 [101, 102] (Scheme 4.39). Tris(trimethylsilyl) ketenimine 303 reacts with aldehydes such as benzaldehyde in the presence of Bp3-OEt2, via the aldol adduct 304, to give the unsaturated nitriles 305, in 99% yield, and HMDSO 7 [103]. 

Flash thermolysis of 4-substituted isoxazol-5(4//)-ones can be used to generate alkynes, isocyanides, aminoisocyanides and ketenimines (77C258, 76HCA2615). Decomposition of the oxime (538) at an oven temperature of 450 °C produces C02, benzonitrile and fulminic acid (539 equation 5) (79AG(E)467). This method thus offers a safe alternative to the synthesis of fulminic acid from the explosive metal fulminates. 

In addition to azomethines and oximes, various heterocumulenes, such as ketenimines, isocyanates and isothiocyanates, can be used to synthesize imidoyl chlorides. For example, addition of chlorine to ketenimines LXIX affords a-chloroimidoyl chlorides LXX... 

Imidoyl bromides are also obtained when oximes are treated with the phosphonium salt XV. For example, reaction of XV with the oxime XVI produces the imidoyl bromide XVII, which can be dehydrohalogenated to the ketenimine XVIII by means of triethylamine ( ). 

VIII. Reaktionen von Phosphinalkylenen mit Nitriloxiden. Synthesemdglichkeiten fiir Azirine, Ketenimine und a,p-ungesattigte Oxime... 

Bei der thermischen Zersetzung der neuen heterocyclischen Verbin-dungen 519 bilden sich je nach EinfluB der Reste R, Ri und R2 Azirine 523 168,169) Ketenimine 524 les.ies) oder a,p-ungesattigte Oxime 522 i 8). 

The matrix photochemistry of phenyl nitrenes becomes more complex when substituents are present that can take an active part in the reactions. For instance, irradiation of azide 79 in Ar matrices gave a product (80) from nitrene insertion into an adjacent CH bond as well as the ring-expanded ketenimine 81. The nitrene center can also react by attack on oxygen. Thus, the photolysis of 2-(methoxycarbo-nyljphenyl azide (82) in Ar matrices gave rise to at least five major products nitrene 83, cycKc ketenimine 84, the two geometrical isomers of ketene-oxime 86, and N-methoxyazetinone 87 (Scheme 10). Products... 

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