Cobalt-Catalyzed 1,4-Hydrovinylation of Allylsilane and Allylboronic Esters for the Synthesis of Hydroxy-Functionalized 1,4-Dienes

Abstract

The cobalt(I)-catalyzed 1,4-hydrovinylation reaction of allyl trimethylsilane and allyl pinacol boronic ester with symmetrical and unsymmetrical 1,3-dienes generates building blocks for the in situ allylboration or the Lewis acid induced allylation reaction utilizing the corresponding allyl silane derivatives. The products of these three-component reactions are hydroxy-functionalized 1,4-dienes which can be used for the synthesis of pyranones. An alternate reaction sequence for the synthesis of the hydroxy-functionalized 1,4-dienes by performing the allylation first followed by the cobalt-catalyzed 1,4-hydrovinylation is also possible. Accordingly, polyfunctionalized complex structures can be generated by both approaches in a convergent fashion.

Hydrovinylation Reactions – Atom‐Economic Transformations with Steadily Increasing Synthetic Potential

“…[31] Eventually, this protocol was used for the synthesis of rac-hepialone (51) as well as for the natural product 52 isolated from vanilla beans. The primary product (49) of the hydrovinylation of allyl pinacolboronic ester with DMB was reacted in situ with various aldehydes to give hydroxy-functionalised 1,4-dienes such as 50 in a one-pot procedure (Scheme 24).…”

Cobalt-catalysed asymmetric hydrovinylation of 1,3-dienes

“…Expansion of the scope of this reaction and several applications of this and related heterodimerization reactions have since been reported. [49][50][51][52] A notable result in this area relevant to the present discussion is the ligand control of regio-and stereoselectivity in the reactions of substituted butadienes with terminal alkenes to give either the branched (8) or linear (9) adduct (Scheme 1). 48,53 Expanded scope of substrates in the cobalt-catalysed hydrovinylation (HV, addition of ethylene) of alkenes and related reactions have been the subject of several recent publications.…”

Cobalt-Catalysed Bond Formation Reactions; Part 2

“…In this respect, the polyene side-chain of moenomycin A was accomplished utilising the 1,4-HV in a key step of the synthesis of the advanced precursor 33 (Scheme 24 The 1,4-HV reactions of allyl silanes and allyl boronic esters with 1,3-dienes have been investigated by the Hilt group for the synthesis of functionalised building blocks which then react in situ with aldehydes in allylboration and allylsilylation reactions in sequential three-component one-pot reactions. 57 The 1,4-HV reaction was further applied towards sequential four-component one-pot reactions utilising a pinacolboron-functionalised isoprene (34). In this process, two regioselective 1,4-HV reactions were used for the regioselective and highly atom-economic synthesis of complex products, such as 35 (Scheme 25).…”