SILYLENE AND DISILENE REACTIONS WITH ELECTRON-POOR 1,3-DIENES - NEW RING-SYSTEMS AND COMPLETE DEGRADATION OF A CF3 GROUP

Photolysis of ((t)Bu(2)Si)(3) (1) or (Me(3)Si)(2)SiR(2), R = Mes, 2,4, 6-(Pr3C6H2)-Pr-i, 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. irradiat ion of 5 in the presence of an excess of 1 leads to complete degradati on 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-dihyd ro-1,5,3,7,2,6-dioxadiazadisilocine and 2,3,6-trihydro-1,4,2,3,6-oxaza trisiline derivatives 12 and 13, The structures of 4, 9, 12, and 13 we re determined by X-ray crystallography.