Cobalt‐Catalyzed Intermolecular Oxidative Isocyanide Insertion with Two Amines: An Approach to Guanidines

Zhu, Tong‐Hao; Wang, Shun‐Yi; Wei, Tian‐Qi; Ji, Shun‐Jun

doi:10.1002/adsc.201400911

“…An interesting example is the synthesis of unsymmetrically substituted arylguanidines 90 using ac obalt catalyst under ultrasound heating (Scheme 23). [52] Thep rocess involves the imidoylative coupling of an aliphatic and an aromatic amine using (t-BuO) 2 as the oxidant (Scheme 24). Thei nitially formed aromatic C-amidinoylcobalt intermediate 92 can be formed by either aT ype IoraTy pe II pathway.…”

Section: Insertions Of Isocyanides Into Heteroatom-metal Bondsmentioning

confidence: 99%

Base Metal Catalyzed Isocyanide Insertions

Collet

¹

,

Roose

²

,

Ruijter

³

et al. 2019

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Isocyanides are diverse C1 building blocks considering their potential to react with nucleophiles, electrophiles, and radicals. Therefore, perhaps not surprisingly, isocyanides are highly valuable as inputs for multicomponent reactions (MCRs) and other one‐pot cascade processes. In the field of organometallic chemistry, isocyanides typically serve as ligands for transition metals. The coordination of isocyanides to metal centers alters the electronic distribution of the isocyano moiety, and reaction pathways can therefore be accessed that are not possible in the absence of the metal. The tunable reactivity of the isocyanide functional group by transition metals has evolved into numerous useful applications. Especially palladium‐catalyzed isocyanide insertion processes have emerged as powerful reactions in the past decade. However, reports on the use of earth‐abundant and cheap base metals in these types of transformations are scarce and have received far less attention. In this Minireview, we focus on these emerging base metal catalyzed reactions and highlight their potential in synthetic organic chemistry. Although mechanistic studies are still scarce, we discuss distinct proposed catalytic cycles and categorize the literature according to 1) the (hetero)atom bound to and 2) the type of bonding with the transition metal in which the (formal) insertion occurs.

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“…An interesting example is the synthesis of unsymmetrically substituted arylguanidines 90 using a cobalt catalyst under ultrasound heating (Scheme ) . The process involves the imidoylative coupling of an aliphatic and an aromatic amine using ( t ‐BuO) 2 as the oxidant (Scheme ).…”

Section: Insertions Of Isocyanides Into Heteroatom–metal Bondsmentioning

confidence: 99%

Base Metal Catalyzed Isocyanide Insertions

Collet

¹

,

Roose

²

,

Ruijter

³

et al. 2019

View full text Add to dashboard Cite

Isocyanides are diverse C1 building blocks considering their potential to react with nucleophiles, electrophiles, and radicals. Therefore, perhaps not surprisingly, isocyanides are highly valuable as inputs for multicomponent reactions (MCRs) and other one‐pot cascade processes. In the field of organometallic chemistry, isocyanides typically serve as ligands for transition metals. The coordination of isocyanides to metal centers alters the electronic distribution of the isocyano moiety, and reaction pathways can therefore be accessed that are not possible in the absence of the metal. The tunable reactivity of the isocyanide functional group by transition metals has evolved into numerous useful applications. Especially palladium‐catalyzed isocyanide insertion processes have emerged as powerful reactions in the past decade. However, reports on the use of earth‐abundant and cheap base metals in these types of transformations are scarce and have received far less attention. In this Minireview, we focus on these emerging base metal catalyzed reactions and highlight their potential in synthetic organic chemistry. Although mechanistic studies are still scarce, we discuss distinct proposed catalytic cycles and categorize the literature according to 1) the (hetero)atom bound to and 2) the type of bonding with the transition metal in which the (formal) insertion occurs.

show abstract

“…The combination of a perester and catalytic Co(II) promotes reaction of isocyanates and a pair of amines, one of which is always an aniline, to generate guanidines . The described mechanism involves addition of the aniline to the carbon of a Co(II) isocyanate, resulting in an amidine.…”

Section: Reactionsmentioning

confidence: 99%