Vicinal diamino functionalities as privileged structural elements in biologically active compounds and exploitation of their synthetic chemistry

Cu(I)-catalyzed diamination of conjugated dienes. Complementary regioselectivity from two distinct mechanistic pathways involving Cu(II) and Cu(III) species

Conjugated dienes can be diaminated at the internal and/or terminal double bonds using Cu(I) as catalyst and N,N-di-t-butyldiaziridinone (1) as nitrogen source. The regioselectivity is highly dependent upon the choice of Cu(I) catalyst and the substituents on diene substrates. The diamination likely proceeds via two mechanistically distinct pathways. The N-N bond of N,N-di-t-butyldiaziridinone (1) is first homolytically cleaved by the Cu(I) catalyst to form four-membered Cu(III) species A and Cu(II) radical species B, which are in rapid equilibrium. The internal diamination likely proceeds in a concerted manner via Cu(III) species A, and the terminal diamination likely involves Cu(II) radical species B. Kinetic studies have shown that the diamination is first-order in N,N-di-t-butyldiaziridinone (1), zero-order in olefin, and first-order in total Cu(I) catalyst, and the cleavage of the N-N bond of 1 by the Cu(I) catalyst is the rate-determining step. The internal diamination is favored by use of CuBr without ligand and electron-rich dienes. The terminal diamination is favored when using CuCl-L and dienes with radical-stabilizing groups.

Catalytic enantioselective desymmetrization of meso-diamines: a dual small-molecule catalysis approach

The desymmetrization of meso-diamines was accomplished via enantioselective monobenzoylation facilitated by the cooperative action of two small-molecule catalysts. A chiral acyl-transfer reagent is formed in situ through the interplay of benzoic anhydride, 4-(dimethylamino)pyridine as a nucleophilic catalyst, and a chiral amide-thiourea cocatalyst.

Recent advances in transition metal-catalyzed sp3 C-H amination adjacent to double bonds and carbonyl groups

Transition metal-catalyzed C-H amination at positions adjacent to double bonds and carbonyl groups is discussed in this critical review. While the focus will center on the recent developments of α-oxidative amination, some historical developments and mutually beneficial reports in the broader field of C-H amination will be discussed. C-H amination has become a viable method for the efficient installation of nitrogen atoms en route to target molecules (89 references).

Synthesis and reactivity of unique heterocyclic structures en route to substituted diamines

Rhodium-catalyzed oxidative cyclization of allylic hydroxylamine-derived sulfamate esters furnishes a novel family of bicyclic aziridines that serve as functional precursors to substituted diamines. Investigations with the N4-Troc form of these heterocycles have led to manifold improvements in reaction performance and scope and have revealed unique differences in the stability and reactivity of such compounds dictated by the choice of N4-protecting group.

Catalytic, Enantioselective Synthesis of Stilbene cis-Diamines: A Concise Preparation of (-)-Nutlin-3, a Potent p53/MDM2 Inhibitor

The first highly diastereo- and enantioselective additions of aryl nitromethane pronucleophiles to aryl aldimines are described. Identification of an electron rich chiral Bis(Amidine) catalyst for this aza-Henry variant was key to this development, leading ultimately to differentially protected cis-stilbene diamines in two steps. This method then became the lynchpin for an enantioselective synthesis of (-)-Nutlin-3 (Hoffmann-LaRoche), a potent cis-imidazoline small molecule inhibitor of p53-MDM2 used extensively as a probe of cell biology and currently in drug development.

[(1R*,2S*)-N-Benzyl-2-phenyl-1-(pyridin-2-yl)-N-(pyridin-2-ylmeth-yl)ethane-1,2-diamine]-dichloridozinc(II)

In the mononuclear zinc title complex, [ZnCl(2)(C(26)H(26)N(4))], the Zn(II) ion is surrounded by three N atoms from a (1R*,2S*)-N(1)-benzyl-2-phenyl-1-(pyridin-2-yl)-N(2)-(pyridin-2-ylmeth-yl)ethane-1,2-diamine (BPPPEN) ligand and two terminal chloride ligands, resulting in a highly distorted environment around the metal atom. The calculated τ parameter of 0.42 indicates that the coordination geometry is approximately square-pyramidal. Hydrogen bonds involving centrosymmetric N-H⋯Cl inter-actions form dimeric structures. The mol-ecules are stacked along the a and b axes.

Complementary regioselectivity in the Cu(I)-catalyzed diamination of conjugated dienes to form cyclic sulfamides

This paper describes the regioselective diamination of conjugated dienes using inexpensive Cu(I) as catalyst and N,N-di-tert-butylthiadiaziridine 1,1-dioxide as nitrogen source. The regioselectivity of diamination is likely due to dual mechanistic pathways which are greatly influenced by reaction conditions and the nature of the diene. A variety of useful internal and terminal cyclic sulfamides can be obtained in good yield.

Evolution of copper(II) as a new alkene amination promoter and catalyst

Copper(II) carboxylates and chiral copper(II) triflate·bis(oxazoline) complexes promote and catalyze intramolecular alkene carboamination, diamination and aminooxygenation reactions, creating an array of nitrogen heterocycles. High diastereoselectivity and enantioselectivity can be achieved in these transformations. This account reviews the discovery and development of these useful and interesting reactions.

Cu(I)-catalyzed regioselective diamination of conjugated dienes via dual mechanistic pathways

This paper describes the Cu(I)-catalyzed regioselective diamination of conjugated dienes using di-tert-butyldiaziridinone as nitrogen source. The internal diamination and terminal diamination likely proceed via two mechanistic pathways. Various dienes can be efficiently diaminated at the internal double bonds with high regio- and diasteroselectivity in good yield using inexpensive CuBr as catalyst.

Modular synthesis of 1,2-diamine derivatives by palladium-catalyzed aerobic oxidative cyclization of allylic sulfamides

Allylic sulfamides undergo efficient aerobic oxidative cyclization at room temperature, mediated by a new Pd catalyst system consisting of 5% Pd(TFA)2/10% DMSO in THF. The synthetic utility of these reactions is enhanced by several features: (1) the sulfamide substrates are accessible in multi-gram scale from the corresponding allylic and primary amines, (2) the cyclic sulfamide products are readily converted to the corresponding 1,2-diamines upon treatment with LiAlH4, and (3) substrates derived from chiral allylic amines cyclize with very high levels of diastereoselectivity.

Modular Synthesis of 1,2-Diamine Derivatives via Palladium-Catalyzed Aerobic Oxidative Cyclization of Allylic Sulfamides

Allylic sulfamides undergo efficient aerobic oxidative cyclization at room temperature, mediated by a new Pd catalyst system consisting of 5% Pd(TFA)(2)/10% DMSO in THF. The synthetic utility of these reactions is enhanced by several features: (1) the sulfamide substrates are accessible in multi-gram scale from the corresponding allylic and primary amines, (2) the cyclic sulfamide products are readily converted to the corresponding 1,2-diamines upon treatment with LiAlH(4), and (3) substrates derived from chiral allylic amines cyclize with very high levels of diastereoselectivity.

An anti-tetraamination of a 1,3-diene unit via cascade annulations of the azulenone scaffold with dicarbonyl azo-compounds

Dense and stereo-controlled integrations of C-N bonds on the azulenone scaffold are achieved by sequential (i) ene, (ii) [6 + 2]-cycloaddition, and (iii) hetero-conjugate addition reactions leading to a topologically complex bis-bridged skeleton.

An effective C-C double bond formation via Cu(I)-catalyzed dehydrogenation

A dehydrogenation method using Cu(I) and either N,N-di-tert-butylthiadiaziridine 1,1-dioxide or N,N-di-tert-butyldiaziridinone is reported. The dehydrogenation allows a facile introduction of C-C double bond(s) into various carbo- and heterocycles such as oxazolines and thiazolines.

Synthetic and mechanistic studies on Pd(0)-catalyzed diamination of conjugated dienes

Various dienes and a triene can be regioselectively diaminated at the internal double bond with good yields and high diastereoselectivity using di-tert-butyldiaziridinone (5) as the nitrogen source and Pd(PPh(3))(4) (1-10 mol %) as the catalyst. Kinetic studies with (1)H NMR spectroscopy show that the diamination is first-order in total Pd catalyst and inverse first-order in PPh(3). For reactive dienes, such as 1-methoxybutadiene (6g) and alkyl 1,3-butadienes (6a, 6j), the diamination is first-order in di-tert-butyldiaziridinone (5) and zero-order in the olefin. For olefins with relatively low reactivity, such as (E)-1-phenylbutadiene (6b) and (3E,5E)-1,3,5-decatriene (6i), similar diamination rates were observed when 3.5 equiv of olefins were used. Pd(PPh(3))(2) is likely to be the active species for the insertion of Pd(0) into the N-N bond of di-tert-butyldiaziridinone (5) to form a four-membered Pd(II) complex (A), which can be detected by NMR spectroscopy. The olefin complex (B), formed from intermediate A via ligand exchange between the olefin substrate and the PPh(3), undergoes migratory insertion and reductive elimination to give the diamination product and regenerate the Pd(0) catalyst.