Diamines, vicinal synthesis

Kim H, Yen C, Preston P, Chin J. Substrate-directed stereoselectivity in vicinal diamine-catalyzed synthesis of warfarin. Org. Lett. 2006 8(23) 5239-5242. 

The asymmetric synthesis of unsymmetrical vicinal diamines by samarium diiodide induced reductive coupling of nitrones derived from aUphatic aldehydes with optically pure N-tert-butanesulfinyl aromatic imines has been recently reported [41]. For example, the reaction between nitrone 55 and... 

Solid-phase synthesis of dihydropteridinones has been achieved from 4,6-dichloro-5-nitropyrimidine <00TL8177>. A series of ethyl 7-aminopteridine-6-carboxylate derivatives has been prepared in one step from the reaction of vicinal diamines as 13-dialky 1-5,6-diamino-2-thiouracils with diethyl ( )-2,3-dicyanobutenedioate <99JHC1317>. The relative binding affinities to human dihydrofolate reductase of new 2,4-diaminopteridine derivatives... 

Using N-tert -butanesulfinilimines instead of carbonyl derivatives, constitutes an efficient synthetic route to optically pure asymmetric vicinal diamines that are widely used in asymmetric synthesis (Scheme 2.116) (536). 

A diastereoselective synthesis of vicinal diamines has been described79. The aldehydes 56 derived from chiral amino acids 55 were converted into the A-benzylimines 57 and the latter were treated with organometallic reagents R2M in the presence of cerium(III)... 

Because vicinal diamines and 2-aminoalcohols are important components of natural products and medicinal agents, and used as ligands for metal-catalyzed reactions, especially in asymmetric synthesis, efficient methods for the compounds have been extensively investigated over the past decade. " ... 

A general strategy for the transformation of cyclic sulfates into vicinal diamines has been developed (Scheme 7) <1995TL9241>. This method has been extended to the synthesis of unsymmetrical diamines and various other amine derivatives by the controlled introduction of a second nucleophile into the reaction sequence <1995TL9241>. 

In 1994, Hanessian and co-workers [50] reported the first examples of metal-free three-dimensional triple-stranded helicates through spontaneous self-assembly of chiral C2-symmetrical diols and chiral C2-symmetrical diamines. The initial observation resulted from the utilization of enantiopure C2-symmetrical vicinal trans-1,2-diaminocyclohexane [51,52] as ligands in the asymmetric dihydroxylations of olefins [53] and as reagents for asymmetric synthesis [54], When equimolar amounts of (5,5)-frfl x-l,2-diaminocyclohexane (28) and its (i ,i )-enantiomer (29) were individually mixed with (5,5)-frfl x-l,2-cyclohexanediol and heated in refluxing benzene, crystals of the respective supraminol complexes 28 30 and 29 30 were formed quantitatively (Scheme 12). This was the physical basis for the separation of racemic diols with tr[Pg.104]

The paUadium-promoted vicinal diamination of alkenes can be achieved according to Scheme 39 the example chosen illustrates how the mechanism and stereochonistry were determined. The independent synthesis of (36) from a qualemized aziridine is also notewordiy. Yields are 60-87% from ter-... 

The structure and the stereochemistry of the 1,2- and 1,4-nitroacetamides were assigned on the basis of spectroscopic analysis and conversion of the 1,2-nitroacetamides to dihydroimidazoles. Variable syn or anti addition was observed depending on the structure of the alkene. Reduction of the nitro group to an amino function by aluminum amalgam allows stereoselective synthesis of vicinal monoacetylated diamines. 

Chiral C2-symmetric vicinal diamines have emerged as powerful tools for the synthesis of enantiomerically pure compounds and are now commonly used as chiral auxiliaries or ligands for a wide array of asymmetric chemical transformations, with efficiencies comparable to those obtained with the closely related... 

Utility. Many asymmetric syntheses have been developed using vicinal diamines as the source of chirality. The major interest lies in their use as precursors for the synthesis of a broad family of bidentate ligands. Many reactions have also been described using the N-alkyl derivatives of these diamines as chiral auxiliaries and protecting groups of aldehydes. Most of these applications generally use the framework of l,2-diphenyl-l,2-diaminoethane (7) or 1,2-diaminocyclohexane (8), whose preparations have been fully described. ... 

Synthesis of Enantiomerically Pure C2-symmetric Vicinal Diamines via Chirality Transfer from DPEN. Several C2-sym-metric vicinal diamines and their derivatives are prepared in optically pure form by chirality transfer from DPEN. For example, condensation of (5, 5)-DPEN with butane-2,3-dione in benzene at the reflux temperature is followed by stereoselective reduction with NaBHsCN and PPTS at -20 °C to afford the (25,35,5R,6R)-piperazine 4 and its diastereomer in a 15 1 ratio (eq 12). The crude product is purified by silica gel column chromatography. Formation of the biscarbamate followed by reductive cleavage of benzylic C-N bonds with lithium in liquid ammonia, and then removal of isobutyloxycarbonyl with HBr in acetic acid results in (/ ,/ )-2,3-diaminobutane dihydrobromide 5 in 99% ee. 

In the last step of a dibromophakellstatin synthesis, PhI(OAc)2 serves well to effect closing of the central piperazinone moiety in what is actually a vicinal diamination reaction. [Pd(OAc)2 - DMSO can also be employed.]... 

Since the late 1980s, 3,6-dihydrothiazines have been used as building blocks for stereoselective synthesis of vicinal amino alcohols, diamines and other highly functionalized amines <86X2979, 88ACR313). 3,6-Dihydrothiazine 1-oxide (214) has been efficiently converted to cry/Aro-sphingosine... 

The Weinreb group has recently developed stereoselective methodology for synthesis of unsaturated vicinal diamine derivatives from dihydrothiazine imines.49 For example, when cycloadduct 54 prepared from (E, )-2,4-hexadiene was treated with phenylmagnesium bromide followed by trimethyl phosphite, E-threo vicinal diamine 57 was formed cleanly in good yield [Ea. <27)1. 

Jung, S. and Kohn, H. (1984) A new reductive procedure for the preparation of vicinal diamines and monoamines. Tetrahedron Letters, 25, 399 02 Jung, S.H. and Kohn, H. (1985) Stereoselective synthesis of vicinal diamines from alkenes and cyanamide. Journal of the American Chemical Society, 107, 2931-2943. 

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