Synthesis and Structure of Eight-Membered Titanium Containing Siloxane Rings

The preparation by different methods of the eight-membered ring compounds (R 1 XTiOSiR 2 2 O) 2 is reported: (2: R 1 =C 5 Η 5 , X=Cl, R 2 =tBu; 3: R 1 =N(SiMe 3 ) 2 , X=C1, R 2 =tBu; 4: R 1 =C 5 Me 5 , X=Cl, R 2 =Ph; 6: R 1 =X=NEt 2 , R 2 =tBu). The six-membered ring Ph 2 SiO[OTiC 5 Me 5 (Cl)] 2 5 is formed together with 4 by the reaction of C 5 Me 5 TiCl 3 and Ph 2 Si(OLi) 2 . Compounds 2 and 4 have been characterized by X-ray structural analysis.