Catalytic asymmetric ring opening of meso-epoxides with aromatic amines in water

[reaction: see text] An operationally simple and environmentally benign protocol for the catalytic asymmetric ring opening of meso-epoxides with aromatic amines has been developed. The reactions proceeded smoothly in the presence of 1 mol % of Sc(OSO3C12H25)3 and 1.2 mol % of a chiral bipyridine ligand in water to afford beta-amino alcohols in high yields with excellent enantioselectivities.     

Samarium iodides catalyzed meso-epoxides ring opening by aromatic amines

Samarium diiodide catalyzes the ring opening of meso-epoxides by several aromatic amines affording β-aminoalcohols at room temperature. The use of bis-binaphthoxy iodo samarium allows an enantioselective desymmetrization of cyclohexene oxide by o-anisidine.     

Enantioselective ring opening of meso-epoxides with thiols catalyzed by a chiral (salen)Ti(IV) complex

A chiral (salen)Ti(IV) complex was an efficient catalyst in the asymmetric ring opening of meso-epoxides 1 with thiols 2 in high yields and good ee.     

A magnetic nanoparticle‐catalyzed regioselective ring opening of epoxides by aromatic amines

Sulfonic acid‐functionalized silica‐coated magnetic Fe₃O₄ nanoparticles were synthesized and applied as a green catalyst for an efficient and environmentally friendly ring opening of epoxides with aromatic amines in good to excellent yields with high chemoselectivity. Clean aminolysis of various aliphatic and aromatic epoxides in ethanol generates β‐hydroxyamines under mild reaction conditions. The synthesized acidic magnetic nanoparticles were recovered using a simple external magnet and successfully reused for five runs without any appreciable loss of catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd.     

Oxirane ring opening reactions with thiols catalyzed by lanthanide complexes

LnCl₃ (Ln = Ce,Sm) and Eu(fod)₃ act as Lewis-acid catalysts in stereo- and regioselective epoxide ring opening reactions with thiols under mild conditions in CH₂Cl₂.     

Highly efficient ring opening reactions of epoxides with deactivated aromatic amines catalyzed by heteropoly acids in water

Heteropoly acid was found to be an effective and efficient catalyst for the ring opening reaction of epoxides with various aromatic amines to produce the corresponding β-amino alcohols in moderate to excellent yields in water. This method provides a new and efficient protocol in terms of mild reaction conditions, clean reaction profiles, small quantity of catalyst, and simple work-up procedure.     

Tri-n-butylphosphane catalyzed ring opening of aziridines with secondary amines

Ring opening of aziridine with dialkyl amine took place readily in the presence of catalytic amounts of tri-n-butylphosphane （10 mol%） in the mixture of CH₃CN/H₂O（10:1）,giving corresponding vicinal diamines in mediate to high yields（58-95%） with good regioselectivitie,while aromatic secondary amine could not react under the same conditions.Tri-n-butylphosphane exhibited different catalytic selectivity to amines from Lewis acid catalysts.     

Zn(OAc)2/podand catalyzed ring opening of epoxides by aromatic amines under solvent-free conditions

A highly regioselective ring opening of epoxides with aromatic amines in the presence of a catalytic amount of Zn(OAc)₂ and a recently synthesized podand under solvent-free conditions is described. The yields of the amino alcohols are uniformly good and the recovered catalyst could be used in new attempts without any purification.     

Enantioselective ring-opening reaction of meso-epoxides with ArSeH catalyzed by heterometallic Ti-Ga-Salen system

The first example of enantioselective ring-opening reaction of meso-epoxides with aryl selenols to give optically active beta-arylseleno alcohol in up to 97% ee was realized, using a chiral Ti-Ga-Salen heterometallic catalyst. A strong synergistic effect of different Lewis acids in the system was exhibited in the catalytic process.     

Rhodium-catalyzed ring opening of vinyl epoxides with alcohols and aromatic amines

[Rh(CO)(2)Cl](2) is an effective catalyst for the ring opening of vinyl epoxides with alcohols and aromatic amines under neutral conditions at room temperature. The reaction occurs with excellent diastereo- and regioselectivity (>20:1) giving the trans-1,2-amino alcohols or alkoxy alcohols for a wide range of substrates. The regio- and stereochemistry of these reactions is complementary to that typically obtained with palladium-catalyzed ring openings of vinyl epoxides.     

Highly atom efficient guanylation of both aromatic and secondary amines catalyzed by simple lanthanide amides

It is demonstrated that the cyclopentadienyl-free simple lanthanide amides [(Me(3)Si)(2)N](3)Ln(mu-Cl)Li(THF)(3)(Ln = La, Sm, Eu, Y, Yb) and Ln[N(SiMe(3))(2)]3 (Ln = Y, Yb) are highly efficient catalysts for the guanylation of both aromatic and secondary amines with a high activity under mild conditions. It is found that these catalysts are compatible with a wide range of solvents and substrates.     

Asymmetric ring opening of meso epoxides with TMSCN catalyzed by (pybox)lanthanide complexes

The asymmetric ring opening of meso epoxides with TMSCN is catalyzed by (pybox)YbCl3 complexes, yielding the beta-trimethylsilyloxy nitrile ring-opened products with good enantioselectivities (83-92% ee). The reaction exhibits a second-order kinetic dependence on catalyst concentration and a first-order dependence on epoxide concentration, consistent with a bimetallic pathway involving simultaneous activation of epoxide and cyanide.     

New development in the enantioselective ring opening of meso-epoxides by various chloride ion silicon sources catalyzed by an o-methoxyaryldiazaphosphonamide Lewis base

New developments in the enantioselective ring opening of meso-epoxides catalyzed by a chiral Lewis base have been achieved using various chloride ion silicon sources. Thus, the use of TMSCl led to enantioselectivities varying from 6 to 98% ee depending on the nature of the considered epoxide.     

Sulfamic acid catalyzed ring opening of epoxides with amines under solvent-free conditions

Sulfamic acid (SA) catalyses the nucleophilic opening of epoxide rings by amines leading to the efficient synthesis of ß-amino alcohols. The reaction works well with aromatic and aliphatic amines in short reaction times and in the absence of solvent. Exclusive trans stereoselectivity is observed for the ring opening of cyclohexene oxide. This method exhibits excellent regioselectivity for preferential nucleophilic attack at the less hindered position during the reaction with unsymmetrical epoxides.     

Enantioselective ring opening of meso aziridines catalyzed by Tridentate Schiff base chromium(III) complexes

[formula: see text] A catalytic method for the enantioselective ring opening of meso aziridines by TMSN3 is described. Tridentate Schiff base chromium complexes derived from 1-amino-2-indanol were identified as the optimal catalysts.     

Microwave-assisted asymmetric ring opening of meso-epoxides with aromatic amines catalyzed by a Ti-S-(−)-BINOL complex

Catalytic asymmetric ring opening of cyclohexene oxide and meso-stilbene oxide with anilines was catalyzed by a Ti-(S)-(−)-BINOL complex to afford β-amino alcohols in high yield (up to 95%) and good enantioselectivities (ee up to 55%) under microwave irradiation. The reaction using a microwave was found to be 10 times faster than traditional oil-bath heating with retention of enantioselectivity.     

Iridium-catalyzed asymmetric ring opening of azabicyclic alkenes by amines

The enantioselective ring-opening reactions of azabicyclic alkenes with primary and secondary aromatic amine nucleophiles are reported using an iridium catalyst generated in situ from 1.5 mol % of [Ir(COD)Cl](2) and 3 mol % of (S)-BINAP. The reaction affords the corresponding trans-1,2-diamine derivatives in moderate to good yields with moderate to high enantioselectivities (up to 97% ee). The trans-configuration of the 1,2-diamino product 2g was confirmed by X-ray crystallography.     

Enantioselective trifluoromethylation of aromatic aldehydes catalyzed by combinatorial catalysts

A new combinatorial catalyst system containing the disodium (R)-binaphtholate prepared in situ and a chiral quaternary ammonium salt was developed for enantioselective trifluoromethylation of aromatic aldehydes in up to 71% ee. A possible intermediate for the binaphtholate activation of the TMSCF₃ and a catalytic cycle were proposed based on the experiments.