ChemInform Abstract: Silicon Compounds with Strong Intramolecular Steric Interactions. Part 59. Silylene and Disilene Reactions with Electron-Poor 1,3-Dienes: New Ring Systems and Complete Degradation of a CF3 Group.

Photolysis of (tBu2Si)3 (1) or (Me3Si)2SiR2, R = Mes, 2,4,6-iPr3C6H2, in the presence of 3,6-bis(trifluoromethyl)-1,2,4,5-tetrazine (5) furnishes silaheterocycles having 3,4,1-diazasilole (6) and 2,5-dihydro-1,3,2,5-diazadisiline (9, 10) ring skeletons. Irradiation of 5 in the presence of an excess of 1 leads to complete degradation of one of the CF3 groups and to a partial rearrangement of the six-membered ring skeleton to give the new ring system 4. Cophotolysis of 1 and 2,5-bis(trifluoromethyl)-1,3,4-oxadiazole provides the 2,6-dihydro-1,5,3,7,2,6-dioxadiazadisilocine and 2,3,6-trihydro-1,4,2,3,6-oxazatrisiline derivatives 12 and 13. The structures of 4, 9, 12, and 13 were determined by X-ray crystallography.