We report the synthesis and reactivity of divinyl‐functionalized syn ‐type tricyclic laddersiloxanes featuring enlarged 10‐8‐10 fused frameworks. The reaction of a silanol precursor with dichloromethylvinylsilane afforded methyl‐substituted derivative 2 in an excellent yield (96%), whereas the bulkier phenyl analog 3 was obtained in a moderate yield (38%) under intensified conditions. Both compounds were formed as mixtures of three isomers and exhibited relatively high thermal stability. Post‐functionalization studies revealed a pronounced steric effect on the reactivity. While both derivatives underwent efficient platinum‐catalyzed hydrosilylation with dimethylphenylsilane, the increased bulk of the silane significantly reduced or suppressed the conversion, particularly for the phenyl‐substituted system. In addition, the thiol‐ene reaction of 2 enabled the incorporation of hydroxyl functionality. These results expand the structural toolbox of functional bat siloxanes and demonstrate their potential as versatile precursors for siloxane‐based architectures.
Liu et al. (Fri,) studied this question.