Intermolecular amination, with

Katritzky developed a facile synthesis of l,2-diaryl(heteroaryl)pyrroles in a two-step procedure from A-allylbenzotriazoles via intramolecular oxidative cyclization in the presence of a Pd(II) catalyst <00JOC8074>. Thus, treating A-allylbenzotriazole (21) with n-butyllithium followed by addition of a diarylimine yielded the (2-benzotriazolyl-l-arylbut-3-en)anilines 22 which were subsequently heated in the presence of the system Pd(OAc)2-PPh3-CUCI2-K2CO3 to undergo intermolecular amination with simultaneous oxidation of the intermediate 3-pyrroline to the pyrroles 23. 

In the sense of an intermolecular amination with heterocyclic amidine derivatives, such as amino azines and diazines, and 2-chloro-3-iodopyridines followed by an intramolecular amination, Maes and coworkers [93] have established a facile synthesis of dipyrido[l,2-a 3 2 -d]imidazole and its benzo-and aza-analogs 101-106 (Scheme 36). 

Later, Arcadi showed that jS-keto-imines react with alkynes intramolecularly to give pyrroles. The intermolecular amination with anilines was later developed by Hayashi and Tanaka using a cationic Au(I) catalyst to form imines (equation 27). More recently, Arcadi etal. developed an intramolecular version for the cyclization of o-alkynylanilines to form indoles (equation and Li reported a... 

Discovered more than a century ago, the Knorr and Paal-Knorr (PK) pyrrole syntheses are similar intermolecular condensations of amines with carbonyl compounds to give pyrroles. 

Iron phthalocyanine is an efficient catalyst for intermolecular amination of saturated C-H bonds. With 1 mol% iron phthalocyanine and 1.5 equiv. PhlNTs, amination of benzylic, tertiary, and ally lie C-H bond have been achieved in good yields (Scheme 31). With cyclohexene as substrate, the allylic C-H bond amination product was obtained in 75% yield, and the aziridination product was found in minor amount (17% yield) [79]. 

Infra-red, microwave, and X-ray photoelectron spectroscopy Infra-red and ultra-violet spectroscopy has been widely used for investigating the structure of intermolecularly hydrogen-bonded complexes in the solid state (Novak, 1974) and in solution (Zundel, 1976, 1978 Clements et al., 1971a,b,c Pawlak et al., 1984). By analysing the infra-red spectra of equimolar liquid mixtures of amines with formic or acetic acid, the relative importance of structures [10] and [11] was estimated (Lindemann and Zundel, 1977). It was proposed that [10] and [11] make equal contributions to the observed structure of the complex when the p -value of the carboxylic acid is approximately two units lower than that of the protonated amine. 

Metal porphyrins have been employed for intermolecular G-H amination with allylic, benzylic, and some saturated... 

Intermolecular amination experiments described by Muller using 02NC,5H4S02N=IPh (NsN=IPh) as the nitrene source underscore the value of certain rhodium(II) catalysts for C-H insertion (Scheme 17.5) [12, 34—36]. In accord with Breslow s finding, dirhodium carboxylates were demonstrated to catalyze the amination of allylic, benzylic, and adamantyl substrates. Notably, structurally related tetracarboxamide dimers fail to give... 

Oxidative amination of carbamates, sulfamates, and sulfonamides has broad utility for the preparation of value-added heterocyclic structures. Both dimeric rhodium complexes and ruthenium porphyrins are effective catalysts for saturated C-H bond functionalization, affording products in high yields and with excellent chemo-, regio-, and diastereocontrol. Initial efforts to develop these methods into practical asymmetric processes give promise that such achievements will someday be realized. Alkene aziridina-tion using sulfamates and sulfonamides has witnessed dramatic improvement with the advent of protocols that obviate use of capricious iminoiodinanes. Complexes of rhodium, ruthenium, and copper all enjoy application in this context and will continue to evolve as both achiral and chiral catalysts for aziridine synthesis. The invention of new methods for the selective and efficient intermolecular amination of saturated C-H bonds still stands, however, as one of the great challenges. 

The coupling of chiral amines with aryl bromides proceeds without racemization by proper choice of ligands. Intermolecular animation of a chiral amine proceeds without loss of enantiomeric purity with Pd(0)-(o-Tol)3P. Synthesis of the optically pure indole 415, an intermediate for the synthesis of a potent ACE inhibitor, has been achieved by the Pd-catalyzed amination of 414, which is prepared by the Heck reaction of bromide 413 and Rh-catalyzed aymmetric hydrogenation [205],... 

Acetals result from oxidative coupling of alcohols with electron-poor terminal olefins followed by a second, redox-neutral addition of alcohol [11-13]. Acrylonitrile (41) is converted to 3,3-dimethoxypropionitrile (42), an intermediate in the industrial synthesis of thiamin (vitamin Bl), by use of an alkyl nitrite oxidant [57]. A stereoselective acetalization was performed with methacrylates 43 to yield 44 with variable de [58]. Rare examples of intermolecular acetalization with nonactivated olefins are observed with chelating allyl and homoallyl amines and thioethers (45, give acetals 46) [46]. As opposed to intermolecular acetalizations, the intramolecular variety do not require activated olefins, but a suitable spatial relationship of hydroxy groups and the alkene[13]. Thus, Wacker oxidation of enediol 47 gave bicyclic acetal 48 as a precursor of a fluorinated analogue of the pheromone fron-talin[59]. 

The aziridination of olefins, which forms a three-membered nitrogen heterocycle, is one important nitrene transfer reaction. Aziridination shows an advantage over the more classic olefin hydroamination reaction in some syntheses because the three-membered ring that is formed can be further modified. More recently, intramolecular amidation and intermolecular amination of C-H bonds into new C-N bonds has been developed with various metal catalysts. When compared with conventional substitution or nucleophilic addition routes, the direct formation of C-N bonds from C-H bonds reduces the number of synthetic steps and improves overall efficiency.2 After early work on iron, manganese, and copper,6 Muller, Dauban, Dodd, Du Bois, and others developed different dirhodium carboxylate catalyst systems that catalyze C-N bond formation starting from nitrene precursors,7 while Che studied a ruthenium porphyrin catalyst system extensively.8 The rhodium and ruthenium systems are... 

More importantly, this silver system catalyzes the intermolecular amination of hydrocarbons, as shown in Table 6.3. In addition to animating weaker benzylic C-H bonds, stronger aliphatic C-H bonds such as those in cyclohexane were also reactive. Although yields with more inert hydrocarbons were modest with the bathophenan-throline system, the discovery of the first silver-catalyzed intermolecular amination opens opportunities for further developments. This reaction favored tertiary cyclic sp3 C-H bonds over secondary cyclic sp3 C-H bonds, and showed limited success with simple linear alkanes. No conversion was observed with any aromatic C-H bonds. The compound NsNH2 was tested as the nitrene precursor with different oxidants. The use of PhI(OAc)2 as oxidant gave the expected amination product with a lower yield, while persulfate and peroxides showed no reactivity. 

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