Lithium Aluminum Amides: New Reagents for the Synthesis of Imines

Solladié‐Cavallo, Arlette; Bencheqroun, M.; Bonne, Frédeérique

doi:10.1080/00397919308011266

Cited by 10 publications

(2 citation statements)

References 6 publications

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“…NMR data of 17 . 1 H NMR, see ref . 13 C NMR {50 MHz, benzene- d 6 , 293 K}: δ 161.0 (d, J CH = 152 Hz, C H), 64.2 (N-CH 2 ) 46.3 32.3, 31.4, 29.2.…”

Section: Methodsmentioning

confidence: 99%

Intermolecular Hydroamination of Terminal Alkynes Catalyzed by Organoactinide Complexes. Scope and Mechanistic Studies

et al. 2001

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Organoactinide complexes of the type Cp* 2 AnMe 2 (An ) Th, U) have been found to be efficient catalysts for the hydroamination of terminal alkynes with aliphatic primary amines. The chemoselectivity and regioselectivity of the reactions depend strongly on the nature of the catalyst and the nature of the amine and show no major dependence on the nature of the alkyne. The hydroamination reaction of the terminal alkynes with aliphatic primary amines catalyzed by the organouranium complexes produces the corresponding imines where the amine and the alkyne are regioselectively disposed in a syn-regiochemistry, whereas for similar reactions with the organothorium complex besides the methyl alkylated imine, dimeric and trimeric alkyne oligomers are also produced. For (TMS)CtCH and EtNH 2 both organoactinides produced the same imine compounds when the reaction is carried out in THF or toluene. In benzene, both imines E and Z (TMS)CH 2 CHNdEt are obtained, the earlier undergo a 1,3-silyl Brook sigmatropic rearrangement toward the enamine, whereas the latter remains unchanged. Mechanistic studies on the hydroamination of (TMS)CtCH and EtNH 2 promoted by the organouranium complex show that the first step in the catalytic reaction is the formation of the bis(amido) complex, found in equilibrium with the corresponding bisamido-amine complex, which loses an amine, yielding a uranium-imido complex. Insertion of the alkyne into the imido bond with subsequent amine protonolysis, isomerization, and product release comprise the primary steps in the catalytic cycle. The kinetic rate law was found to follow an inverse kinetic order in amine, a first order in complex, and a zero order in alkyne, with ∆H q ) 11.7(3) kcal mol -1 , ∆S q ) -44.5(8) eu. The turnoverlimiting step is the release of an amine from the bisamido complex yielding the imido complex.The key organoactinide intermediate for the intermolecular hydroamination reaction was found to be the corresponding actinide-imido complexes. For both actinides the complexes have been characterized, and for thorium the single-crystal X-ray diffraction was studied. A plausible mechanistic scenario is proposed for the hydroamination of terminal alkynes and aliphatic primary amines.3

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“…NMR data of 17 . 1 H NMR, see ref . 13 C NMR {50 MHz, benzene- d 6 , 293 K}: δ 161.0 (d, J CH = 152 Hz, C H), 64.2 (N-CH 2 ) 46.3 32.3, 31.4, 29.2.…”

Section: Methodsmentioning

confidence: 99%

Intermolecular Hydroamination of Terminal Alkynes Catalyzed by Organoactinide Complexes. Scope and Mechanistic Studies

et al. 2001

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“…A similar mechanism can be put forward in the synthesis of imines from aldehydes and ketones with lithium aluminum amides. [168] The latter compounds are prepared by reaction of 4-5 equivalents of benzylamine or propylamine with lithium aluminum hydride in diethyl ether or tetrahydrofuran. Yields are excellent for aldehydes and ketones.…”

Section: Nhr 3 Homentioning

confidence: 99%

Product Class 7: Imines

Padwa¹,

Bellus²

2005

Category 4. Compounds With Two Carbon Heteroatom Bonds

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Compounds with the general structure R 1 R 2 C=NR 3 , referred to as imines, were first obtained by Schiff via condensation of ketones and aldehydes with primary amines. Therefore, the condensation products are also called Schiff bases. In addition, the nominations azomethine, ketimine (derived from ketones), aldimine (derived from aldehydes), and anil (derived from anilines) are in use. It is recommended that the terms imine(s), ketimine(s), or aldimine(s) are used, rather than Schiff base(s) or azomethine(s).Since imines have to be considered as analogues of carbonyl compounds, many of the chemical properties are similar to the latter. Imines are used in new C-C bond formations, and reactions with electrophiles (e.g., aldehydes, alkyl halides), and the C=N moiety can undergo nucleophilic reactions. Generally, imines are very useful compounds in organic synthesis, as they are used in several syntheses of aza-heterocyclic compounds. Most imines are stable in an alkaline medium and therefore can be dried over potassium hydroxide. In diluted acid, however, they are easily hydrolyzed. In many cases intermediary imines cannot be isolated because of their lability. The presence of a C=N bond creates the possibility for E/Z isomerism (syn/anti). It has been recognized that such geomet-

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