Organo-1,3,2-dioxasilaheterocycles

Degradable Silyl Ether Polymers Synthesized by Sequence-Controlled Cationic Terpolymerization of 1,3-Dioxa-2-silacycloalkanes with Vinyl Ethers and Aldehydes

“…Synthesis of 1,3-Dioxa-2-silacycloalkanes. 2,2-Dimethyl-1,3dioxa-2-silacycloalkanes were synthesized by the condensation of dimethoxydimethylsilane (TCI, >98.0%) and diol 20,21 using indium-(III) trifluoromethanesulfonate (Sigma-Aldrich) as a catalyst at room temperature. After condensation, the reaction mixture was concentrated to remove methanol, which was generated as a byproduct.…”

“…22 In addition, seven-membered monomers are generally stable, and eight-or more-membered monomers are significantly less stable unless oxygen or nitrogen atoms or aromatic rings are introduced into the ring. 21 Nevertheless, detailed studies on the polymerization of 1,3-dioxa-2-silacycloalkanes have not been conducted. Homopolymerization and copolymerization of 1,3-dioxa-2-silacycloalkanes potentially yield polymers that both are degraded by acids, bases, or fluoride ions and exhibit properties derived from alkyl groups and silyl ether moieties.…”

“…To synthesize new silicon-containing polymers, we focused on 1,3-dioxa-2-silacycloalkanes (Scheme ), which are silicon counterparts of cyclic acetals and have a silicon atom instead of a carbon atom at the 2-position. The syntheses of various 1,3-dioxa-2-silacycloalkanes have been investigated for several decades. − A typical synthetic procedure of 1,3-dioxa-2-silacycloalkanes is the condensation of a diol and a silyl compound such as dimethoxydimethylsilane by an acid catalyst. , Interestingly, it was reported that five-membered monomers form dimers, while six-membered monomers spontaneously polymerize . In addition, seven-membered monomers are generally stable, and eight- or more-membered monomers are significantly less stable unless oxygen or nitrogen atoms or aromatic rings are introduced into the ring .…”

“…The syntheses of various 1,3-dioxa-2-silacycloalkanes have been investigated for several decades. − A typical synthetic procedure of 1,3-dioxa-2-silacycloalkanes is the condensation of a diol and a silyl compound such as dimethoxydimethylsilane by an acid catalyst. , Interestingly, it was reported that five-membered monomers form dimers, while six-membered monomers spontaneously polymerize . In addition, seven-membered monomers are generally stable, and eight- or more-membered monomers are significantly less stable unless oxygen or nitrogen atoms or aromatic rings are introduced into the ring . Nevertheless, detailed studies on the polymerization of 1,3-dioxa-2-silacycloalkanes have not been conducted.…”

Base-Catalyzed Dehydrogenative Si-O Coupling of Dihydrosilanes: Silylene Protection of Diols

“…The established procedure for silylene protection of diols is their reaction with dichlorosilanes in the presence of double stoichiometric amounts of a hydrochloric acid scavenger, usually pyridines or tertiary amines. 2 Aside from twice equimolar formation of pyridinium or ammonium chlorides, this method is afflicted with a few more drawbacks. The ditert-butylsilylene group is commonly used but its precursor t-Bu 2 SiCl 2 is relatively unreactive, often requiring harsher reaction conditions.…”