Transition-Metal-Catalyzed Diarylation of Isocyanides with Triarylbismuthines for the Selective Synthesis of Imine Derivatives.

Shintaro Kodama,Akihiro Nomoto,Shin-Ichi Kawaguchi,Yohsuke Kobiki,Yuki Yamamoto,Akiya Ogawa,Hitomi Matsubara,Cong Chi Tran

doi:10.3390/ma14154271

Shintaro Kodama, Akihiro Nomoto + Show 6 more

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https://doi.org/10.3390/ma14154271

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Abstract

The transition-metal-catalyzed diarylation of isocyanides with triarylbismuthines was investigated in detail, and rhodium catalysts such as [RhCl(nbd)]2 were found to selectively afford N-alkyl diaryl ketimines. On the other hand, palladium-catalyzed diarylation proceeded with the incorporation of two molecules of isocyanide, preferentially yielding N,N’-dialkyl or N,N’-diaryl α-diimines. In addition, a cascade synthesis of 2,3-diarylquinoxalines starting from the palladium-catalyzed diarylation of isocyanides with triarylbismuthines was successfully achieved.

Highlights

Synthesis of Imine Derivatives.As the chemistry of heteroatom-containing compounds has significantly grown in recent decades, the properties and reactivities of high-period elements have gradually attracted more attention [1,2,3,4,5,6,7,8,9,10,11,12]
In our previous paper [42], we reported that Pd(OAc)2 -catalyzed diarylation of isocyanides 2 with BiAr3 1 selectively afforded α-diimines 3
We proposed a possible pathway for the Pd(OAc)2 -catalyzed diarylation of isocyanide 2 with triarylbismuthine 1 to afford α-diimine 3, the essence of which is shown in Scheme 5

Summary

Introduction

As the chemistry of heteroatom-containing compounds has significantly grown in recent decades, the properties and reactivities of high-period elements have gradually attracted more attention [1,2,3,4,5,6,7,8,9,10,11,12]. Bismuth is the heaviest of the group 15 elements, and its organic and inorganic compounds are regarded to be nontoxic [13]. Organobismuth compounds are generally unstable due to the weakness of the carbon–bismuth bond. Synthetic applications of triarylbismuthines [14,15,16] have been investigated by many organic chemists [17,18,19,20,21,22,23,24,25] and N-, O-, S- and C-arylation reactions have been developed using triarylbismuthines as arylating reagents

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