Preparation of Organozinc Reagents via Catalyst Controlled Three-Component Coupling between Alkyne, Iodoarene, and Bis(iodozincio)methane

Abstract

Three-component coupling between an alkyne, iodoarene, and bis(iodozincio)methane yields allylic zinc with a tetrasubstituted alkene moiety in the presence of a nickel catalyst. The reaction proceeds via aryl nickelation of the alkyne and subsequent cross-coupling with bis(iodozincio)methane. Meanwhile, the same combination in the presence of a palladium and cobalt catalyst gives tetrasubstituted alkenylzinc. The reaction proceeds via a palladium-catalyzed cross-coupling of iodoarene with bis(iodozincio)methane followed by a cobalt-catalyzed benzylzincation of alkyne.

Nickel-Catalyzed Hydroarylation of Alkynes under Reductive Conditions with Aryl Bromides and Water

“…Three-component coupling reactions involving alkynes and organometallic reagents are more common with the second-row transition metals Rh − and Pd because less reactive organometallic reagents (such as boronic acids) will participate in transmetalation with these metals; the reagents responsible for transmetalation and electrophilic trapping are more likely to be compatible in the same reaction flask. Still, there are several interesting reports of three-component reactions that involve carbometalation across an alkyne catalyzed by first-row transition metals such as Co and Ni. ,,, …”

Preparation of 2-Aryl-3-silyl- and 2-Aryl-3-germyl-1,3-butadienes via Arylnickelation and Zinciomethylation

“…shown in Scheme 5, the diarylalkyne without benzyl ether group 14 was converted into 15 via the allylzinc 17. 5 The oxidative insertion of the nickel catalyst into C-O bond of propargylic ether is not crucial. Thus, the pathway shown in Scheme 1, in which arylnickelation to alkyne initiates the transformation may be more plausible.…”

“…4 In one approach, it was used as the nucleophilic component, along with aryl iodide and alkyne, to produce allyl zinc. 5 In this instance, when propargyl ether is used as the alkyne with a leaving group, 1,3-butadiene can be obtained by a three-component assembling reaction via elimination. 6,7 The 2,3-disubstituted-1,3-butadienes obtained by this reaction have a cross-diene structure and this is included in the structures of various useful substances.…”