Synthesis of Multiply Substituted Alkylidene Silacyclohexadiene Derivatives via Palladium-Catalyzed Insertion of Alkynes into Alkylidene Silacyclobutenes

Abstract

Palladium-catalyzed insertion of activated alkynes into silacyclobutene derivatives proceeded smoothly to afford exo-alkylidenesilacyclohexadiene derivatives of unique structure with diversified conjugation systems in high isolated yields. Interesting regioselectivity of insertion, which afforded only one regioisomer or a mixture of two or more regioisomers, was also observed.

Construction of Chiral Tetraorganosilicons by Tandem Desymmetrization of Silacyclobutanes/Intermolecular Dehydrogenative Silylation

“…[1] However,t oo ur knowledge,o nly three examples have been reported for the synthesis of dibenzosiloles with silicon stereogenic centers. [13][14][15] We commenced our study by using SCB [23,24] 1a and 2chlorothiophene 2a as the model substrates under the catalysis of Rh(cod)Cl (10 mol %) ( Table 1). No reaction took place in the absence of al igand (entry 1).…”

Palladium- and Nickel-Catalyzed Carbon−Carbon Bond Insertion Reactions with Alkylidenesilacyclopropanes

“…Reversible oxidative addition of alkylidenesilacyclopropane 3 provides palladasilacyclobutane 15 2,3,5,10,12. For terminal alkynes and allenes, migratory insertion into the palladium–silicon bond3,8,10,12,14,17,34-36 affords intermediate 16 . Reductive elimination then provides product ( Z )- 4 .…”

Formation of α‐Lithio Siloles from Silylated 1,4‐Dilithio‐1,3‐Butadienes: Mechanism and Applications

“…Di-iodides 4 d-e can be easily obtained from diynes 8 a-b by the known method as illustrated in Scheme 4. [13][14][15] Lithiation of these di-iodides could give the corresponding dilithio reagents 1 d-e, which would undergo similar transformation to give silole derivatives as the only products (Scheme 5). For example, dilithio reagent 1 d would convert into a-silylated silole 3 d in excellent yield at room temperature after quenching with water.…”