Synthesis of difunctional organooxasilacycloalkanes

2,8-Dichloro-2,4,4,6,6,8,10,10,12,12-decamethyl-5-carbacyclohexasiloxane, 4 ,7-dichloro-2,2,4,7-tetramethyl-1,3-dioxa-2,4,7-trisilacycloheptane, and 4, 8-dichloro-2,2,4,8-tetramethyl-1,3-dioxa-2,4,8-trisilacyclooctane were prep ared for the first time by heterofunctional condensation of 1,1,7,7-tetrach loro-1,3,3,5,5.7-hexamethyl-4-carbatetrasiloxane with 1,3-dihydroxy-1,1,3,3 -tetramethyldisiloxane, of 2,2,5,5-tetrachloro-2,5-disilahexane with dihydr oxydimethylsilane. and of 2,2,6,6-tetrachloro-2,6-disilaheptane with dihydr oxydimethylsilane. respectively. Hydrolysis of the resulting compounds affo rded the corresponding dihydroxy derivatives, and trans-isomers of some of these derivatives were isolated in individual form.