Spacer-bridged ladder compounds - syntheses, structures and synthetic applications

The reaction of alpha,omega-bis(organodichlorostannyl)alkanes [R(Cl-2)SnCH2 ](2)Z with their corresponding organotin oxides [R(O)SnCH2](2)Z or (t-Bu2Sn O)(3) provides the new spacer-bridged tetraorganodistannoxanes {[R(Cl)SnCH2 ](2)Z]O}(n) (22, Z = CH2, R = Me3SiCH2; 23, Z = CH2, R = Me3CCH2; 24, Z = C H2CH2, R = Me3SiCH2; 25, Z = CH2CH2, R = Me3CCH2; 26, Z = CH2CH2, R = Me2CH CH2; 27, Z = Me2Si, R = Me3SiCH2). The acetate substituted derivative 28 {[ R(AcO)SnCH2](2)CH2]O}(n) (R = Me3SiCH2) is obtained by reaction of 22 with silver acetate or by treatment of the organotin oxide [R(O)SnCH2](2)CH2 (R = Me3SiCH2) with acetic acid. The crystal structures of 23, 24, and 28 are described and reveal that these compounds adopt double ladder structures. D epending on the identity of Z and R in chloroform solution the compounds ar e either dimers (n = 2, 25-28) or tetramers (n = 4, 22-24). Also reported a re preliminary studies on the catalytic activity in acylation reactions of compounds 22, 24-26, and 28. (C) 1999 Elsevier Science S.A. All rights rese rved.