Telechelic oligo(dimethy1siloxane)s 6 and7 with chloro-, cyano-or aminopropyl end groups were synthesized from the corresponding chlorodimethylsilanes 2 ac and a-hydro-w-hydroxyoligo-(dimethylsi1oxane)s 4 and 5. The w-cyano derivatives 6 b and 7 b were reduced to the 4-aminobutyl derivatives 8 a and 8 b with LiAIH,. 8a was subsequently transformed into 1,7-bis(4-maleimidobutyl)-l,1,3,3,5,5,7,7-octamethyltetrasiloxane (10) by reaction with maleic anhydride, via the intermediate dimaleamic acid 9. The products were characterized by IR, 'H, 29Si, and 13C NMR spectroscopy. CH, CH, x = 3 o r 4 a) Part 2: cf. *). 0025-1 16X/89/$03.00 2438 B. Boutevin, F. Guida-Pietrasanta, J.-J. RobinHowever, these ring-opening polymerizations produce an equilibrium mixture of linear and cyclic species and still recently, J. E Mc Grath et al.4) specified that "it would be highly desirable to obtain well-defined functional oligosiloxanes of narrow molecular weight distribution". This can be achieved with our condensation method, starting with a-hydro-w-hydroxyoligo(dimethylsi1oxane)s which exhibit narrow molecular weight distributions, and which are actually available.
Results and discussionFirst, monochlorosilanes 2a-c were synthesized in good yields (49 to 78%) via hydrosilylation of functional allylic compounds in hexane with dimethylchlorosilane in the presence of H,PtCl,5).H,PtCI, Hexane 18 h/70 "C