Synthesis and characterization of half-sandwich Rh, Ir complexes containing mono-thiolate-ortho-carborane ligand

Two binuclear complexes [Cp^∗M(Cl)Carb^S]₂ (Cp^∗ = η⁵-C₅Me₅, M = Rh (1a), Carb^S = SC₂(H)B₁₀H₁₀, Ir (1b)) were synthesized by the reaction of LiCarb^S with the dimeric metal complexes [Cp^∗MCl(μ-Cl)]₂ (M = Rh, Ir). Four mononuclear complexes Cp^∗M(Cl)(L)Carb^S (L = BuⁿPPh₂, M = Rh (2a), Ir (2b); L = PPh₃, M = Rh (4a), Ir (4b)) were synthesized by reactions of 1a or 1b with L (L = BuⁿPPh₂ (2); PPh₃ (4)) in moderate yields, respectively. Complexes 3a, 3b, 5a, 5b were obtained by treatment of 2a, 2b, 4a, 4b with AgPF₆ in high yields, respectively. All of these compounds were fully characterized by IR, NMR, and elemental analysis, and the crystal structures of 1a, 1b, 2a, 2b, 4a, 4b were also confirmed by X-ray crystallography. Their structures showed 3a, 3b and 5a, 5b could be expected as good candidates for heterolytic dihydrogen activation. Preliminary experiments on the dihydrogen activation driven by these half-sandwich Rh, Ir complexes were done under mild conditions.     

3-Amino- and 3-acylamido-2-phosphonopyridines: synthesis by Pd-catalyzed P-C coupling, structure and conversion to pyrido[b]-anellated PC-N heterocycles

Palladium catalyzed cross-coupling of 3-amino- and 3-acylamido-2-bromopyridines 1a-f with triethyl phosphite allowed the synthesis of 3-amino- and 3-acylamido pyridine-2-phosphonic acid diethyl esters 2a-f, whereas nickel catalysts, although providing access to related anilido-2-phosphonates, proved inactive. Reduction of the aminophosphonate 2a with LiAlH₄ afforded 3-amino-2-phosphinopyridine (3a), which was cyclocondensed with dimethylformamide dimethyl acetal (DMFA) via phosphaalkene intermediates 4a to the novel pyrido[b]-anellated 1,3-azaphosphole 5a. Reaction of amidophosphonates 2b-f with LiAlH₄ did not result in the expected reductive cyclization, as shown by closely related anilido-2-phosphonates, but led to product mixtures containing N-secondary 3-amino-2-phosphinopyridines 3b-f as the main or major component. The conversion of 3b,d,e with DMFA to 5b,d,e provides first examples of N-substituted pyrido[b]-anellated azaphospholes. Structures were confirmed by multinuclear NMR and X-ray crystallography (for 2c, 3b).     

Phosphorus-nitrogen compounds part 22. Syntheses, structural investigations, biological activities and DNA interactions of new mono and bis (4-fluorobenzyl) spirocyclophosphazenes

The reactions of hexachlorocyclotriphosphazene, N₃P₃Cl₆, with mono (1 and 2) and bis(4-fluorobenzyl) diamines (3-5), FPhCH₂NH(CH₂)_nNHR (RH or FPhCH₂-), produce mono (1a and 2a) and bis(4-fluorobenzyl) monospirocyclophosphazenes (3a-5a). The tetraaminomonospirocyclophosphazenes (1b-2d) are obtained from the reactions of the partly substituted phosphazenes (1a and 2a) with excess pyrrolidine, morpholine and 1,4-dioxa-8-azaspiro[4,5]decane (DASD), respectively. The tetrachlorobis(4-fluorobenzyl) monospirocyclophosphazenes (4a and 5a) with excess pyrrolidine, morpholine and DASD afford the fully substituted bis(4-fluorobenzyl) monospirocyclophosphazenes (4b, 4d-5d) in boiling THF. In addition, monochlorobis(4-fluorobenzyl) monospirocyclophosphazenes (4e and 4f) have also been isolated from the reactions with excess morpholine and DASD in boiling THF. The structural investigations of the compounds have been verified by elemental analyses, MS, FTIR, ¹H, ¹³C, ¹⁹F (for 1d and 2d), ³¹P NMR, HSQC and HMBC techniques. The crystal structures of 3a, 4a, 5a and 2b have been determined by X-ray crystallography. The compounds 2a-5a, 1b-2d, 4b, 4d-5d, 4e and 4f have been screened for antibacterial effects on bacteria and for antifungal activity against yeast strains. The compounds 1b and 4b showed antimicrobial activity against three species of bacteria, Bacillus subtilis, Bacillus cereus and Staphylococcus aureus, and two fungi, Candida albicans and Candida tropicalis. Minimum inhibitory concentrations (MIC) were determined for 1b and 4b. The MIC values were found to be 5000 μM for each bacteria. The most effective compound, 4b has exhibited activity with a MIC of 312 μM for C. albicans and 625 μM for C. tropicalis. DNA-binding and the nature of the interaction with pBR322 plasmid DNA are studied. All of the compounds induce changes on the DNA mobility and intensity. Prevention of HindIII digestion with the compounds indicates that the compounds bind with AT nucleotides in DNA.     

Synthesis, structure and photo-physical properties of phosphorus-supported fluorescent probes

Various phosphorus-supported fluorescent probes have been synthesized by the condensation reaction of multi-functional phosphorus hydrazides with various fluorophore-containing carboxaldehydes. Compounds, thus prepared, in this study are (PhO)₂P(O)[N(Me)-NCH-R] (1a, 1b), Ph₂P(O)[N(Me)-NCH-R] (2b, 2c, 2d), PhP(O)[N(Me)-NCH-R]₂ (3b, 3c), P(S)[N(Me)-NCH-R]₃ (4b, 4c), P(O)[N(Me)-NCH-R]₃ (5a, 5b, 5c), N₃P₃(O₂C₁₂H₈)₂[N(Me)-NCH-R]₂ (6a, 6b, 6c), N₃P₃(O₂C₁₂H₈)[N(Me)-NCH-R]₄ (7a, 7b, 7c, 7d) and N₃P₃[N(Me)-NCH-R]₆ (8b, 8c), where R=1-pyrenyl (a), 9-anthracenyl (b), 9-phenanthryl (c) and 7-(N,N′-diethylamino)-3-coumarinyl (d). All of these compounds have been characterized by various analytical techniques including ³¹P{¹H} NMR spectroscopy. Compounds 1b, 2b, 3b, 4b, 5b, 5c and 6d have also been characterized by single crystal X-ray analysis. All of these phosphorus-supported compounds exhibit excellent fluorescence properties in aqueous solution at near physiological conditions.     

Synthesis, characterization, and derivatization of some novel types of fluorinated mono- and bis-imidazolidineiminothiones with antitumor, antiviral, antibacterial, and antifungal activities

A series of thirty eight novel imidazolidineiminothiones (6a-g, 10a-h, 13a,b, 15a-d, and 16a), 5-thioxoimidazolidine-2,4-diones (7a-d, 11a-e, 14a,b, and 16b), and bis-imidazolidineiminothiones (17-20) with various fluorinated aromatic substituents at N-(1) and N-(3) were prepared in 75-85% yields. The imidazolidineiminothiones were synthesized from fluorinated N-arylcyanothioformanilides and substituted aromatic isocyanates, and by the reactions of fluorinated aromatic isocyanates with fluorinated and non-fluorinated aromatic N-arylcyanothioformanilides. Subsequent hydrolysis of selected products produced the corresponding 5-thioxoimidazolidine-2,4-diones. Preliminary screening of several compounds against Ehrlich ascites carcinoma (EAC) cells indicated that 6f and 16a were the most active (90% and 80% inhibition, respectively). Further evaluation for cytotoxicity against other tumor cell lines gave IC₅₀ values ranging from 0.67 to 3.83 μg/mL, where compounds 15a and 16a were markedly active against all cell lines. This highlights the synergistic effect of the suitably positioned fluorinated substituents on N-(1) and N-(3) of the imidazolidineiminothiones. Compounds 6a,e-g, 10a-c, 13b, 15a-d, and 17-20 were tested against microbial organisms (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typhi, and Sarcina lutea), and fungal strains (Candida albicans, Aspergillus niger, and Aspergillus flavus). Whereas compound 6a exhibited the highest antibacterial activity against Gram positive and Gram negative bacteria, 13b displayed the strongest antifungal activity against all fungal strains, reaching as high as 30 mm. Finally, 15a,b,d were subjected to in vitro testing of antiviral activity against hepatitis A virus (HAV), human herpes simplex virus 1 (HSV1), and Coxsackie B4 (COxB4) viral strain, where 15b was the most effective, reducing virus plaque count of HSV1 and COxB4 by 50% and 60%, respectively.     

A one-pot, two step synthesis of 2,2-disubstituted 1-nitroalkenes

The reactions of ketones 1a-o, nitromethane 2, and a stoichiometric amount of piperidine 3a or ethylenediamine 3b in the presence of mercaptan 6a in THF or CH₃CN solution give high yields of β-nitrosulfides 7a-o. The latter can be oxidized by 8a (m-CPBA or m-CPBA/AcOH) at 0°C, 8b (H₂O₂/AcOH), or 8c (H₂O₂) at room temperature, thus generating β-nitroalkylsulfoxides 9a-o, which then undergo elimination to produce medium to high yields of 2,2-disubstituted-1-nitroalkenes 5a-o, when refluxed in a solution of ClCH₂CH₂Cl (1,2-dichloroethane). After preparation from 1a-o, 2, 3, and 6a, 7a-o were oxidized with 8a, 8b, or 8c in a mixture of CH₃CN and ClCH₂CH₂Cl to generate β-nitrosulfoxides 9a-o, which then underwent elimination under refluxing under one-pot conditions. Compounds 14 and 15g were also prepared using 13, 2, 3b, and 6, in a similar manner.     

Stabilization of (N-methyleneamino)imidoylketenes: synthesis of dipyrazolo[1,2-a;1′,2′-d][1,2,4,5]tetrazines

Thermolysis of substituted methyl 1-methyleneamino-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates 2a,b led to substituted dimethyl 3,9-dioxo-1,5,7,11-tetrahydro-1H,7H-dipyrazolo[1,2-a;1′,2′-d][1,2,4,5]tetrazine-1,7-dicarboxylates 4a,b and methyl 2,5-dihydro-5-oxo-1H-pyrazole-3-carboxylates 5a,b as minor products. The structure of compound 4a was determined by X-ray crystallography. The proposed mechanism of this conversion includes generation of (N-methyleneamino)imidoylketenes 6a,b and its intramolecular transformation to azomethine imines—5-oxo-2,5-dihydropyrazole-1-methylium-2-ides 7a,b, which undergo dimerization in head-to-tail manner yielding products 4a,b and partially hydrolyse to compounds 5a,b.     

Reaction of quinidine acetate, epiquinidine and its acetate in superacid: formation of gem-difluoro derivatives with or without rearrangement

In HF-SbF₅, quinidine 1a or its dihydrochloride cyclises previously obtained with usual acids. A similar reaction is observed in the presence of CCl₄. Under similar conditions quinidine acetate 1b and epiquinidine acetate 2b dihydrochlorides both yield 10,10-difluoro derivatives epimeric at C-3, 6 and 7, and 9c and 10b, and a rearranged difluoro derivative 8b and 11b, respectively. Epiquinidine 2a leads to the expected analogues 10a and 11a and to a ketone 9a. Formation of gem-difluoro compounds implies chloro intermediates at C-10, precursors of α-chlorocarbenium ions, which are trapped by a fluoride ion and which lead by halogen exchange to the products.     

Synthesis, properties, and oxidizing function of 6-substituted 7,9-dimethylcyclohepta[b]pyrimido[5,4-d]pyrrole-8(7H),10(9H)-dionylium tetrafluoroborates

Uracil-annulated heteroazulenes, 6-substituted 7,9-dimethylcyclohepta[b]pyrimido[5,4-d]pyrrole-8(7H),10(9H)-dionylium tetrafluoroborates 7a,b·BF₄⁻, which are the isoelectronic compounds of 5-dezazaflavin, were synthesized. X-Ray crystal analysis and MO calculations were carried out to clarify the structural characteristics of 7a,b·BF₄⁻. The stability of cations 7a,b is expressed by the pK_R+ values which were determined spectrophotometrically to be 10.9 and 11.2, respectively. The electrochemical reduction of 7a,b exhibited high reduction potentials at −0.84 and −0.87 (V vs Ag/AgNO₃) upon cyclic voltammetry (CV). A good linear correlation between the pK_R+ values and reduction potentials (E1_red) of 7a,b·BF₄⁻ and reference compounds 4·BF₄⁻ and 5·BF₄⁻ was obtained. In a search of the reactivity, reactions of 7a,b·BF₄⁻ with some nucleophiles, hydride and diethylamine, were carried out to clarify that the introduction of nucleophiles to give regio-isomers is dependent on the nucleophile. The photo-induced oxidation reactions of 7a,b·BF₄⁻ toward some alcohols under aerobic conditions were carried out to give the corresponding carbonyl compounds in more than 100% yield [based on compounds 7a,b·BF₄⁻], suggesting the oxidizing function of 7a,b·BF₄⁻ toward alcohols in the autorecycling process.     

Improved approaches and structures of new ferrocenyl carbene complexes of chromium, tungsten, and molybdenum

Ferrocenyllithium reacts with M(CO)₆ (M = Cr, W, Mo) in THF to give, after alkylation at oxygen, the corresponding carbene complexes 3a-c in good yield. Complexes 3a,b were characterized by X-ray analysis. These complexes react with pentylamine to give the corresponding aminocarbene complexes 7a-c and with allylamine to give, in the case of chromium and tungsten, the corresponding and expected aminonocarbene complexes 8a,b, and for molybdenum, complex 9c in which the double bond is already coordinated to the metal. 8a,b could be converted in 9a,b in excellent yield. The structure of 9a could be confirmed by an X-ray analysis. Alkylations at nitrogen could be carried on complex 9c as well as on complexes 9a,b.     

Activation of C-H and C-Br bonds in cyclopalladation reactions of Schiff base ligands: Influence of the benzylidene ring substituents

Reaction of Pd(AcO)₂ with the Schiff base ligands 2-Br-4,5-(OCH₂O)C₆H₂C(H)N(Cy) (a) and 4,5-(OCH₂CH₂)C₆H₃C(H)N(Cy) (b) leads to the cyclometallated compounds [Pd{2-Br-4,5-(OCH₂O)C₆HC(H)N(Cy)-C6,N}(μ-O₂CMe)]₂ (1a) and [Pd{4,5-(OCH₂CH₂)C₆H₂C(H)N(Cy)-C6,N}(μ-O₂CMe)]₂ (1b), respectively, via C-H activation. Treatment of a with Pd₂(dba)₃ gave [Pd{4,5-(OCH₂O)C₆H₂C(H)N(Cy)-C2,N}(μ-Br)]₂ (6a), via C-Br activation. The metathesis reaction of 1a and 1b with aqueous sodium chloride gave the corresponding cyclopalladated dimers with bridging chloride ligands, 2a and 2b, respectively. Treatment of the halogen-bridged compounds with tertiary tri- and diphosphines in the appropriate molar ratio gave the mono and dinuclear compounds 3a-5a, 7a-9a and 3b-5b. The structure of compounds 3a, 4a, 5a, 8a, 2b, 3b and 5b has been determined by X-ray diffraction analysis.     

Pyrrolide-imine benzyl complexes of zirconium and hafnium: synthesis, structures, and efficient ethylene polymerization catalysis

A series of pyrrolyl-imines HL^1-6 was prepared by the condensation of pyrrole-2-carboxyaldehyde with different amines. The reaction of 2 equiv of pyrrolyl-imine with tetrabenzyl complexes of hafnium and zirconium M(CH₂Ph)₄ (M=Hf or Zr) gave dibenzyl complexes (L^3-6)₂M(CH₂Ph)₂, which were characterized by NMR spectroscopy and crystal structure analysis. NMR spectra of the complexes with secondary alkyl substituents at the imine nitrogen (isopropyl: 3a, 4-tert-butylcyclohexyl: 4a and 4b) suggest that rapid racemization between Δ and Λ configurations occurs in solution on the NMR time scale. The complexes with pyrrolide-imine ligands with a tertiary alkyl group such as tert-butyl (5a and 5b) or 1-adamantyl (6a and 6b) at the imine nitrogen possess cis-configured benzyl groups. Hafnium complexes 5a and 6a react with B(C₆F₅)₃ in bromobenzene-d₅ to give the corresponding cationic benzyl complexes, which exhibit high activity for ethylene polymerization (5a: 2242 kg-polymer/ mol-Hf h bar, 6a: 2096 kg-polymer/ mol-Hf h bar). Zirconium complexes 5b and 6b display a remarkably high ethylene polymerization activity when activated with methylaluminoxane (5b: 17,952 kg-polymer/mol-Zr h bar, 6b: 22,944 kg-polymer/mol-Zr h bar).     

Synthesis of new tetracyclic 7-oxo-pyrido[3,2,1-de]acridine derivatives

A series of (±)3-hydroxyl- and 2,3-dihydroxy-2,3-dihydro-7-oxopyrido[3,2,1-de]acridines were synthesized for antitumor evaluation. These agents can be considered as analogues of glyfoline or (±)1,2-dihydroxyacronycine derivatives. The key intermediates, 3,7-dioxopyrido[3,2,1-de]acridines (15a,b or 24a,b), for constructing the target compounds were synthesized either from 3-(N,N-diphenylamino)propionic acid (14a,b) by treating with Eaton’s reagent (P₂O₅/MsOH) (Method 1) or from (9-oxo-9H-acridin-10-yl)propionic acid (23a-c) via ring cyclization under the same reaction conditions (Method 2). Compounds 15a,b and 24a,b were converted into (±)3-hydroxy derivatives (25a-d), which were then further transformed into pyrido[3,2,1-de]acridin-7-one (28a-d) by treating with methanesulfonic anhydride in pyridine via dehydration. 1,2-Dihydroxylation of 28a-d afforded (±)cis-2,3-dihydroxy-7-oxopyrido[3,2,1-de]acridine (29a-d). Derivatives of (±)3-hydroxy (25a,b) and (±)cis-2,3-dihydroxy (29a-d) were further converted into their O-acetyl congeners 26a,b and 30a-d, respectively. We also synthesized 2,3-cyclic carbonate (31, 32, and 33) from 29a-c. The anti-proliferative study revealed that these agents exhibited low cytotoxicity in inhibiting human lymphoblastic leukemia CCRF-CEM cell growth in culture.     

Salen-ligands based on a planar-chiral hydroxyferrocene moiety: Synthesis, coordination chemistry and use in asymmetric silylcyanation

Condensation of the O-protected hydroxyferrocene carbaldehyde (S_p)-1 with suitable diamines, followed by liberation of the hydroxyferrocene moiety leads to a new type of ferrocene-based salen ligands (3). While the use of ethylenediamine in the condensation reaction yields the planar-chiral ethylene-bridged ligand [(S_p,S_p)-3a], reaction with the enantiomers of trans-1,2-cyclohexylendiamine gives rise to the corresponding diastereomeric cyclohexylene-bridged systems [(S,S,S_p,S_p)-3b and (R,R,S_p,S_p)-3c], which feature a combination of a planar-chiral ferrocene unit with a centrochiral diamine backbone. Starting with the ferrocene-aldehyde derivative (R_p)-1, the enantiomeric ligand series (3d/e/f) is accessible via the same synthetic route.The (S_p)-series of these newly developed N₂O₂-type ligands was used for the construction of the corresponding mononuclear bis(isopropoxy)titanium (4a/b/c), methylaluminum (5a/b/c) and chloroaluminum-complexes (6a/b/c), which were isolated in good yields and identified by X-ray diffraction in several cases. The aluminum complexes (5/6) were successfully used in the Lewis-acid catalyzed addition of trimethylsilylcyanide to benzaldehyde, yielding the corresponding cyanohydrins in 45-62% enantiomeric excess.     

Synthesis and pharmacological evaluation of 6a,7-dihydro-6H,13H-pyrazino[1,2-a;4,5-a′]diindole analogs as melatonin receptor ligands

The synthesis of two melatonin-derived analogs of the novel 6a,7-dihydro-6H,13H-pyrazino[1,2-a;4,5-a′]diindole ring system is described. The non-methoxy and methoxy analogs, 4a and 4b were prepared in seven steps starting from indoline-2-carboxylic acid 5a and 5-methoxyindoline-2-carboxylic acid 5b, respectively. While 4a exhibited micromolar affinities for both melatonin receptors, the methoxy analog 4b displayed moderate affinity for MT₂ receptors (K_i=0.41 μM) being 4.4-fold higher than for the MT₁ subtype.     

Synthesis of (−)-lentiginosine, its 8a-epimer and dihydroxylated pyrrolizidine alkaloid from d-glucose

The d-glucose derived α,β-unsaturated ester 5 on 1,2-acetonide deprotection, oxidative diol cleavage followed by treatment with N-benzylamine in the presence of NaBH₃CN undergoes reductive amination and a concomitant intramolecular conjugate addition reaction leading to the formation of dihydroxypyrrolidine-ester 6a and monohydroxypyrrolidine-γ-lactone 6b. Intermediates 6a and 6b were efficiently converted to (−)-lentiginosine 3a, its 8a-epimer 3b, and pyrrolizidine azasugar 4 in good overall yield.     

2-(1-Isopropyl-2-benzimidazolyl)-6-(1-aryliminoethyl)pyridyl transition metal (Fe, Co, and Ni) dichlorides: Syntheses, characterizations and their catalytic behaviors toward ethylene reactivity

A series of 2-(1-isopropyl-2-benzimidazolyl)-6-(1-aryliminoethyl)pyridyl metal complexes [iron (II) (1a-6a), cobalt (II) (1b-6b) and nickel (II) (1c-6c)] were synthesized and fully characterized by elemental and spectroscopic analyses. Single-crystal X-ray diffraction analyses of five coordinated complexes 5a, 3b, 5b, 1c and 2c reveal 5a and 5b as distorted trigonal-bipyramidal geometry, and 3b, 1c and 2c as distorted square pyramidal geometry. All complexes performed ethylene reactivity with the assistance of various organoaluminums. The iron complexes displayed good activities in the presence of MAO and MMAO. Upon activated by Et₂AlCl, the cobalt analogues showed moderate ethylene reactivity, while the nickel analogues exhibited relatively higher activities.     

Synthesis and reactivity of new functionalized Pd(II) cyclometallated complexes with boronic esters

Treatment of the functionalized Schiff base ligands with boronic esters 1a, 1b, 1c and 1d with palladium (II) acetate in toluene gave the polynuclear cyclometallated complexes 2a, 2b, 2c and 2d, respectively, as air-stable solids, with the ligand as a terdentate [C,N,O] moiety after deprotonation of the -OH group. Reaction of 1j with palladium (II) acetate in toluene gave the dinuclear cyclometallated complex 5j. Reaction of the cyclometallated complexes with triphenylphosphine gave the mononuclear species 3a, 3b, 3c, 3d and 6j with cleavage of the polynuclear structure. Treatment of 2c with the diphosphine Ph₂PC₅H₄FeC₅H₄PPh₂ (dppf) in 1:2 molar ratio gave the dinuclear cyclometallated complex 4c as an air-stable solid.Deprotection of the boronic ester can be easily achieved; thus, by stirring the cyclometallated complex 3a in a mixture of acetone/water, 3e is obtained in good yield. Reaction of the tetrameric complex 2a with cis-1,2-cyclopentanediol in chloroform gave complex 2c after a transesterification reaction. Under similar conditions complexes 3a and 3d behaved similarly: with cis-1,2-cyclopentanediol, pinacol or diethanolamine complexes 3c, 3b, 3g and 3f, were obtained. The pinacol derivatives 3b and 3g experiment the Petasis reaction with glyoxylic acid and morpholine in dichloromethane to give complexes 3h, and 3i, respectively.     

d- and l-Serine, useful synthons for the synthesis of 24-hydroxyvitamin D3 metabolites. A formal synthesis of 1α,24R,25-(OH)3-D3, 24R,25-(OH)2-D3 and 24S,25-(OH)2-D3

d- and l-Serine have been used for the enantioselective synthesis of tosylates 7a and 7b, useful building blocks for the synthesis of triols 5a and 5b which have already been obtained via a diastereoselective synthesis and used for the synthesis of 2a, 2b and 2c. We have thus performed a formal synthesis of 24S,25-(OH)₂-D₃, 24R,25-(OH)₂-D₃ and 1α,24R,25-(OH)₃-D₃.     

Stereocontrolled conversion of some optically active (4S,5R)-dihydroisoxazoles into acyclic 3-acetamido-1,2-diols

Optically active (4S,5R)-dihydroisoxazoles 5a-c (90-91% ee) have been prepared by reaction of the epoxyketones 4a-c with hydroxylamine. Reduction of compounds 5a and 5b using lithium aluminium hydride took place exclusively from the Re face to give (1R,2S,3S)-1,3-disubstituted-3-aminopropane-1,2-diols 6a and 6b. These amino-diols were characterised by N-acetylation and the stereochemical sense of the hydride reduction was confirmed by conversion of amides 7a and 7b into α-amino acid derivatives 10a and 10b.