Intramolecular 1,3-diamines

A Cu(OAc)2-catalyzed intramolecular diamination of alkenes using sulfamide substrates such as compound 214 provides a route to fused thiadiazolidines 215 (Equation 48) <2005JA11250>. In this reaction, the transition metal activates the alkene toward nucleophilic attack by the first nitrogen, then becomes displaced by the second nitrogen nucleophile (a net M +z to M reduction). 

Scheme 4.10 Cyclic ureas from intramolecular diamination of alkenes, n = 1, 2.

The intramolecular diamination of alkenes could be further extended to the synthesis of cyclic guanidines (Eq. (4.29)) [31]. In this case, copper chloride represents the optimum oxidant and the reaction proceeds equally well for both five and six-membered annelation products. 

Other aminooxygenation reactions were observed as undesired pathways in the development of intramolecular diamination with sulfamates and guanidines, respectively [89, 90]. In addition, Michael described the conditions to use alcoholic solvents in order to intercept the described carboamination reaction from... 

The attractive combination of transition metals and iodobenzene diacetate as strong oxidant allowed the subsequent development of additional diamination reactions. For example, in the presence of a conventional ttiphenylphosphino-gold(l)chloride complex, intramolecular diamination using ureas as nitrogen sources proceeds within a gold(l/lll) cycle with results that are comparable to the mentioned paUadium(II/IV) catalysis [99]. However, as the initial step consists of an anti-aminoauration, this reaction provides the opposite stereochemistry with respect to the overall product configuration. 

The development of suitable conditions for the intramolecular diamination of alkenes using iodine(III) promoters was initially addressed by Wirth within his aminooxygenation reactions. For the case of tosylated urea precursor, the corresponding diamination product could be isolated, but a general profile towards diamination was not reported [54]. 

For intramolecular diaminations, a novel chiral hypervalent iodine reagent 36 was successfully synthesized and used in the enantioselective cyclization of guanidine and sulfodiamine derivatives 35 to give cyclized products 37, which can be... 

Thus, like in the ease of dibromopyridines, higher reaetivity of hetaryl bromides in nucleophilic substitution reactions, as compared to benzene derivatives, did not result in higher yields of the maeroeyeles, products of intramolecular diamination. 

Another type of bifunctional catalysis has been noted with a,cn-diamines in which one of the amino groups is primary and the other tertiary. These substituted diamines are from several times to as much as 100 times more reactive toward imine formation than similar monofunctional amines. This is attributed to a catalytic intramolecular proton transfer. 

Formation of diamines from dinitro compounds, which are unable to interact intramolecularly, presents no problem. Very large volumes of diaminotoluene, a precursor to toluene diisocyanate, are produced by hydrogenation of dinitrotoluene over either nickel or palladium-on-carbon. Selective hydrogenation of one or the other of two nitro groups is much more of a challenge, but a number of outstanding successes have been recorded. A case in point is the hydrogenation of 2,4-dinitroaniline (11) to 4-nitro-l,2-benzenediamine (12) (2) or to 2-nitro-l,4-benzenediamine (10). 

If an aromatic o-diamine such as 1,2-diaminobenzene (2.24) is diazotized in dilute aqueous acid, the 2-aminobenzene-l-diazonium ion formed first (2.25) undergoes a rapid intramolecular N-azo coupling reaction to give 1,2,3-benzotri-azole (2.26). Both amino groups of 2.24 can, however, be diazotized in concentrated acid (Scheme 2-18), forming the bis-diazonium ion 2.27. 1,3- and 1,4-diamines must also be bisdiazotized in concentrated acids in order to avoid inter-molecular N- or C-coupling. 

N-donor ligand. The reaction appears to proceed via an acyclic iminoplatinum(II) intermediate that undergoes a subsequent intramolecular cyclization. Some mechanistic aspects of this versatile reaction have been elucidated.225,226 A4-l,2,4-oxadiazolines have been prepared by the [2+3] cycloaddition of various nitrones to coordinated benzonitrile in m-[PtCl2( D M SO)(PhCN)] precursors.227,228 Racemic and chiral [PtCl2(PhMeSO)(PhCN)] complexes have also been used in order to introduce a degree of stereoselectivity into the reaction, resulting in the first enantioselective synthesis of A4-l,2,4-oxadiazolines, which can be liberated from the complexes by the addition of excess ethane-1,2-diamine. 

Hultgren, V. M. Atkinson, I. M. Beddoes, R. L. Collison, D. Garner, C. D. Helliwell, M. Lindoy, L. F. Tasker, P. A. Formation of folded complexes retaining intramolecular H-bonding in the extraction of nickel(II) by phenolic oxime and aliphatic diamine ligands. Chem. Commun. 2001, 573-574. 

The oxidation of PIB occurs mainly via intramolecular addition of dioxygen to double bonds of polymer. The reaction of peroxyl radical addition to the phenoxyl radical leads to the formation of quinolide peroxide (see Chapter 15). This peroxide is unstable, and its decomposition provokes the degradation of PIB. Another reaction predominates in case of aromatic diamine. 

Versions of these aminocyclopropanations of terminal alkenes can also be applied intramolecularly. Terminally ethenyl-substituted N,N-dialkylcarboxamides such as 67 yield l-(dialkylamino)bicyclo[n.l.O]alkanes such as 68, while (w-alkenylamino)carboxa-mides such as 69 and 71 lead to 1 -alkyl-2-azabicyclo u.l.0]alkanes such as 70 and 72 (Scheme 11.20) [86,118], and N-allylamino acid N,N-dialkylamides furnish bicyclic diamines (see below). 

---