Synthesis and characterization of sulfide/sulfone-containing 18-8-18-membered-ring ladder-type siloxanes

Innovative macrocyclic 14-membered molecule (5) and tricyclic 18-8-18-membered-ring ladder-type siloxane-based compound (7), with sulfide units inserted in the backbone were prepared through B(C6F5)(3)-catalyzed Piers-Rubinsztajn reaction. Further oxidation of 5 and 7 with m-CPBA enables the synthesis of the novel sulfonyl-containing cyclic and ladder-type compound (8 and 9) in high yields. Both tricyclic ladder-type products (7 and 9) show superior thermostability and their well-defined syn-type structures were determined by X-ray crystallographic analysis. The compounds 7 and 9 may become promising building blocks for various new materials.