Reactions of a Silanediyl with Carbon−Oxygen and Carbon−Nitrogen Double Bonds

Silanediyl 2 (generated by thermolysis of cyclotrisilane 1) reacts with benzophenone, tetracyclone, and fluorenone to yield products, which may originate from highly reactive siloxiranes as intermediates. However, using adamantanone as ketone, stable siloxirane 24 is obtained. The interaction of 2 with benzophenone anil or 36 gives heterocyclic compounds 31 and 37, respectively. The involvement of silaziridines in these reactions, as well as in the reactions of 1 with 1,4-diaza-1,3-butadienes 41a and b, which yield the expected formal [4 + 1] cycloaddition products, remains questionable.