Preparation and Reaction Chemistry of Novel Silicon-Substituted 1,3-Dienes

Abstract

2-Silicon-substituted 1,3-dienes containing non transferrable groups known to promote transmetallation were prepared by Grignard chemistry and enyne metathesis. These dienes participated in one pot metathesis/Diels-Alder reactions in regio-and diastereoselective fashions. Electron-rich alkenes showed the fastest rates in metathesis reactions, and ethylene, a commonly used metathesis promoter slowed enyne metathesis. 2-Pyridyldimethylsilyl and 2-thienyldimethylsilyl substituted Diels-Alder cycloadducts participated in cross-coupling chemistry and the 2-thienyldimethylsilyl substituted cycloadducts underwent cross-coupling under very mild reaction conditions.

Boron and Silicon-Substituted 1,3-Dienes and Dienophiles and Their Use in Diels-Alder Reactions

“…Several procedures for cleavage and functionalization of the silicon tether in these dienes were also reported. In 2015, we reported synthesis of a number of new silicon-substituted 1,3-butadienes (128) via reaction of the Grignard reagent generated from chloroprene (126) with silyl electrophiles (Scheme 34) [32]. Diels-Alder reactions with a number of dienophiles were performed and the yields were highest with the 2-thienyldimethylsilyl-substituted diene.…”

Development of a General Method for the Hiyama–Denmark Cross-Coupling of Tetrasubstituted Vinyl Silanes

“…This area has seen prior development. For example, Hiyama, Denmark, and others have reported the coupling of di- and trisubstituted thienyl vinyl silanes; , however, our attempts to prepare tetrasubstituted thienyl vinyl silanes were not successful. Likewise, Hiyama–Denmark reactions of pyridyl silanes have also been reported; however, Itamo and Yoshida have previously shown that tetrasubstituted systems do not undergo cross-coupling .…”

Cobalt-Catalyzed (E)-Selective Hydrosilylation of 1,3-Enynes for the Synthesis of 1,3-Dienylsilanes

“…On the other hand, silyl groups are easily converted to other important functional groups . Therefore, it is easy to imagine that silyl-substituted 1,3-dienes have diverse reactivity, and indeed, they have been applied in many organic transformations. − …”