Synthesis of 4-Aryl- and 4-Alkyl-2-silyl-1,3-butadienes and Their Diels−Alder/Cross-Coupling Reactions

Abstract

An ene-yne cross methasis of silyl-substituted alkynes and alkenes has been developed as a route to 4-aryl- and 4-alkyl-2-silyl-substituted 1,3-dienes. The dienes prepared were used to affect highly diastereoselective Diels-Alder reactions and then the silicon-substituted Diels-Alder cycloadducts were used in Hiyama cross-coupling reactions. The cross-coupling reactions enable these silicon dienes to be used as synthons for a variety of other dienes one might prepare and need access to. Two of the silicon-substituted Diels-Alder cycloadducts and one of the Hiyama cross-coupling products were also characterized by X-ray crystallography.

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

“…In 2010, our group published an enyne metathesis route to 2-silicon-substituted 1,3-dienes (95) (Scheme 26) [24]. We then studied their Diels-Alder reactions and the Hiyama-Denmark cross coupling reactions (96) of the silicon-substituted cyclohexene products of those Diels-Alder reactions.…”

Ruthenium‐Catalyzed Multicomponent Reactions: Access to α‐Silyl‐β‐Hydroxy Vinylsilanes, Stereodefined 1,3‐Dienes, and Cyclohexenes

“…We envisioned the application of the generated dienes in the electrocyclic Diels–Alder reaction (Scheme ) . The discovery of the quantitative isomerization reaction prompted us to investigate the application of the ( E )‐dienes in the desired Diels–Alder reaction.…”

“…We envisioned the application of the generated dienes in the electrocyclic Diels-Alder reaction (Scheme 10). [25,26] The discovery of the quantitative isomerization reactionp rompted us to investigate the application of the (E)-dienes in the desired Diels-Alder reaction. Interestingly,w ec ould demonstratea n iterative multicomponent one-pot protocol to carry out five synthetic operations in one flask, generating highly complex products from simple starting materials in ah ighly selective fashion.Asequence consisting of hydrosilyalation,a llylation, elimination, isomerization, and as ubsequent Diels-Alder reaction was attempted.…”

The Hiyama Cross‐Coupling Reaction: New Discoveries

“…The introduction of an aryl group by substitution of the silicon moiety in compounds 52 was easily achieved by palladium catalysis in the presence of copper(I) iodide and TBAF to afford products 53 (Scheme ) 47…”