Carbosiloxandendrimere mit terminalen SiH-Bindungen

An efficient method for the preparation of carbosiloxane dendrimers with end-grafted SiH-bonds is given by using the alcohols HOCH(Me)(CH₂)₄SiMe_3 − nH_n (4a: n = 1, 4b: n = 2, 4c: n = 3), which themselves are accessible by the hydrosilylation of MeCOCH₂CH₂CHCH₂ (1) with the chlorosilanes HSiMe_3 − nCl_n (2a: n = 1, 2b: n = 2, 2c: n = 3) and hydrogenation of the latter species with LiAlH₄]. Alcohols 4a-4c can be used as starting materials for the preparation of carbosiloxane dendrimers of the 1^st-3^rd generation. For the synthesis of the 1^st generation dendrimers, Me_4 − mSiCl_m (5a: m = 1, 5b: m = 2, 5c: m = 3, 5d: m = 4) is reacted with 4a-4c in presence of NEt₃ as base. The dendritic molecules Me_4 − mSiOCH(Me)(CH₂)₄SiMe_3 − nH_n]_m (n = 1: 6a, m = 1; 6b, m = 2; 6c, m = 3; 6d, m = 4. n = 2: 7a, m = 1; 7b,m = 2; 7c, m = 3; 7d, m = 4. n = 3: 8a, m = 3; 8b, m = 4) are thereby obtained in excellent yield. Carbosiloxane dendrimers of the 2^nd and 3^rd generation with a MeSiO₃- or SiO₄-core can be isolated from the reaction of MeSi(OCH₂CH₂CH₂SiMe₂Cl)₃ (9), MeSi(OCH₂CH₂CH₂SiMeCl₂)₃ (11), Si(OCH₂CH₂CH₂SiMe₂Cl)₄ (13) and MeSi(OCH₂CH₂CH₂SiMe(OCH₂CH₂CH₂SiMe₂Cl)₂)₃ (15) with 4a or 4b, respectively, under similar reaction conditions. Thereby MeSiOCH₂CH₂CH₂SiMe₂OCH(Me)(CH₂)₄SiMe₂H]₃ (10), MeSiOCH₂CH₂CH₂SiMeOCH(Me)(CH₂)₄SiMe_3 − nH_n]₂]₃ (12a, n = 1; 12b, n = 2), SiOCH₂CH₂CH₂SiMeOCH(Me)(CH₂)₄SiMe₂H]₂]₄ (14) and MeSiOCH₂CH₂CH₂SiMeOCH₂CH₂CH₂SiMe₂OCH(Me)(CH₂)₄SiMe_3 − nH_n]₂]₃ (16) are formed as colourless oils.Compounds 3, 4, 6-8, 10, 12, 14 and 16 were characterised by elemental analysis as well as spectroscopic (IR, NMR) and mass spectrometric (ESI-TOF) studies.