Ruthenium carbenes as catalysts in stereoselective ene–yne metathesis/Diels–Alder and ene–yne metathesis/Diels–Alder/cross coupling multicomponent reactions

Abstract

Please cite this article as: Junker CS, Welker ME, Ruthenium Carbenes as Catalysts in stereoselective ene-yne Metathesis/Diels-Alder and ene-yne Metathesis/Diels-Alder/Cross coupling multicomponent reactions, Tetrahedron (2012Tetrahedron ( ), doi: 10.1016Tetrahedron ( /j.tet.2012 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractAn ene-yne cross metathesis of silyl substituted alkynes and alkenes followed by a Diels-Alder reaction of the metathesis product 2-silyl-1,3-dienes has been developed.The dienes thus prepared in situ were shown to participate in highly diastereoselective Diels-Alder reactions. In one case the silicon substituted Diels-Alder cycloadduct was subsequently used without isolation and purification in a Hiyama cross coupling reaction.The cross coupling reactions enable these silicon dienes to be used as synthons for a variety of other dienes.

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

“…In one case, we showed that an enyne metathesis/Diels-Alder/cross coupling sequence could be completed with only one reaction workup but addition of alumina (to chelate Ru) and its removal by filtration was required prior to cross coupling to yield 112. In 2012, we extended our earlier enyne metathesis work and showed that if the Hoveyda-Grubbs catalyst was used for the metathesis then enyne metathesis and Diels-Alder reactions could be run as one-pot multicomponent reactions (Scheme 29) [28]. In one case, we showed that an enyne metathesis/ Diels-Alder/cross coupling sequence could be completed with only one reaction workup but addition of alumina (to chelate Ru) and its removal by filtration was required prior to cross coupling to yield 112.…”

“…In 2012, we extended our earlier enyne metathesis work and showed that if the Hoveyda-Grubbs catalyst was used for the metathesis then enyne metathesis and Diels-Alder reactions could be run as one-pot multicomponent reactions ( Scheme 29 ) [ 28 ]. In one case, we showed that an enyne metathesis/Diels-Alder/cross coupling sequence could be completed with only one reaction workup but addition of alumina (to chelate Ru) and its removal by filtration was required prior to cross coupling to yield 112 .…”

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.…”

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

“…Initially, we prepared a number of transition metal-substituted dienes [1,2] for these studies but, more recently, we have been interested in the investigation of silicon- and boron-substituted dienes [3,4,5,6,7]. We have reported the preparation of 2-silicon-substituted 1,3-butadienes by a variety of synthetic routes and demonstrated that they could be used in sequential Diels-Alder/cross-coupling reactions [8,9,10,11,12,13]. Here we report the preparation of new 2-silicon-substituted 1,3-dienes containing silicon substituents known to promote transmetallation (hence, the ability to participate in cross-coupling reactions under very mild conditions) and their Diels-Alder/cross-coupling reactions.…”