Efficient guanylation of aromatic and heterocyclic amines catalyzed by cyclopentadienyl-free rare earth metal amides

Wu, Yinyin; Wang, Shaowu; Zhang, Lijun; Yang, Gaosheng; Zhu, Xiancui; Liu, Chao; Yin, Chengwei; Rong, Jiewei

doi:10.1016/j.ica.2008.12.030

Cited by 43 publications

(8 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Wang et al first reported that rare-earth-metal catalyst precursors having Ln–N bonds could act as good catalysts for the guanylation of primary aromatic amines or secondary amines with carbodiimides . Other catalyst precursors having Ln–N bonds were also explored. − For homoleptic trivalent rare-earth-metal precursors, the catalytic cycle is initiated by the disassociation of one supporting ligand (Scheme b). If there is a bridging ligand in the heteroleptic trivalent rare-earth-metal precursors, an intramolecular acid–base reaction between an amine and a ligand occurs to give a Ln–N species (Scheme c).…”

Section: Four Different Types Of Guanylation Mechanismsmentioning

confidence: 99%

Mechanistic Considerations of the Catalytic Guanylation Reaction of Amines with Carbodiimides for Guanidine Synthesis

Zhang

2015

Organometallics

View full text Add to dashboard Cite

Catalytic guanylation reactions of amines with carbodiimides have received increasing attention because of the atom-economical preparation of guanidines since 2003. To date, more than 40 catalysts including transition metals, main-group metals, and rare-earth metals have been designed and tested for the guanylation reaction to construct acyclic and cyclic guanidines. In this review, we present a mechanistic consideration on catalytic guanylation reactions of amines with carbodiimides for guanidine synthesis to elucidate its development and importance. Four different types of reaction mechanisms have been well categorized: [2 + 2]-cycloaddition/protonation, insertion/protonation, activation of carbodiimide/nucleophilic addition/intramolecular protonation, and protonation/nucleophilic addition/disassociation. It is useful to understand these reaction processes in order to accelerate the rapid development in related areas to meet the growing need for guanidines.

show abstract

Section: Four Different Types Of Guanylation Mechanismsmentioning

confidence: 99%

Mechanistic Considerations of the Catalytic Guanylation Reaction of Amines with Carbodiimides for Guanidine Synthesis

Zhang

2015

Organometallics

View full text Add to dashboard Cite

show abstract

“… 8 In 2003, Richeson et al reported the catalytic guanylation reaction between primary arylamines and unactivated carbodiimides for the first time using a titaniumimido complex as a catalyst at elevated temperatures. 9 Further, the guanylation reaction of primary arylamines and carbodiimides has been investigated using transition-, 10 rare-earth-, 11 and main group metal complexes. 12 Recently, we reported various titanium( iv ) metal complexes and zinc( ii ) metal complex as precursors for the catalytic guanylation reaction of carbodiimides.…”

Section: Introductionmentioning

confidence: 99%

Aluminium alkyl complexes supported by imino-phosphanamide ligand as precursors for catalytic guanylation reactions of carbodiimides

et al. 2022

View full text Add to dashboard Cite

show abstract

“…In recent years, the guanylation chemistry involving arylamines has enjoyed increasing attention sparked by the discovery of highly active transition metal and lanthanide catalysts. − Additionally, group 1 and 2 metal complexes have recently been shown to exhibit high activity toward this organic transformation, thus expanding the list of active guanylation catalysts to main group metals. − Although the insertion of carbodiimides into Al−C/N bonds of Al alkyl/amide species such as [Al(NMe 2 ) 3 ] 2 ( 1 ) is known, examples of catalytic guanylation of amines using organometallic catalysts involving such species have remained undocumented until recently . Despite the similarities of primary arylamines and 1,1-disubstituted hydrazines, to the best of our knowledge, metal-catalyzed hydroamination of carbodiimides with hydrazines to form aminoguanidines has not been reported.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Aluminum-Catalyzed Hydro-amination/-hydrazination of Carbodiimides

Koller

Bergman

2010

Organometallics

View full text Add to dashboard Cite

The catalytic activity of commercially available [Al(NMe2)3]2 (1) and a dimethyl aluminum guanidinate complex toward the hydro-amination/-hydrazination of carbodiimides was studied. The guanidinate-supported complex 2 was prepared via salt metathesis reactions of AlMe2Cl and an in situ generated lithium guanidinate reagent. X-ray crystallographic studies revealed the influence of the guanidinate ligand on the Al metal center. Hydroamination reactions were successfully carried out at room temperature with 2 as the catalyst, while 1 proved to be ineffective under these conditions. On the contrary, both 1 and 2 were active toward the hydro-hydrazination of carbodiimides, which were run at elevated temperatures (120 °C). Consequently, the reaction temperature had a significant influence on the choice of the catalyst since the catalytically active species can be generated from various precatalysts under different conditions. The formation of guanidines and aminoguanidines showed a high functional group tolerance and typically proceeded with excellent yields at low catalyst loadings. X-ray crystallographic studies of compound 4a revealed interesting structural features of the previously unknown aminoguanidine products. The independently isolated Al aminoguanidinate complex 5 showed catalytic activity toward hydro-hydrazination chemistry and provided valuable evidence in support of the proposed reaction mechanism.

show abstract

Efficient guanylation of aromatic and heterocyclic amines catalyzed by cyclopentadienyl-free rare earth metal amides

Cited by 43 publications

References 39 publications

Mechanistic Considerations of the Catalytic Guanylation Reaction of Amines with Carbodiimides for Guanidine Synthesis

Mechanistic Considerations of the Catalytic Guanylation Reaction of Amines with Carbodiimides for Guanidine Synthesis

Aluminium alkyl complexes supported by imino-phosphanamide ligand as precursors for catalytic guanylation reactions of carbodiimides

Highly Efficient Aluminum-Catalyzed Hydro-amination/-hydrazination of Carbodiimides

Contact Info

Product

Resources

About