An asymmetric organocatalytic one-pot strategy for the construction of spirooctahydroacridine-3,3'-oxindole scaffolds has been successfully developed by means of a domino Michael/Povarov reaction sequence. The one-pot protocol affords the chiral spirocyclohexaneoxindoles bearing an octahydroacridine motif with five stereocenters in good to high yields (up to 89 % yield) with excellent to perfect diastereoselectivities (up to >20:1 d.r.) and enantioselectivities (up to >99 % ee). This highly efficient one-pot domino procedure will allow diversity-oriented syntheses of this intriguing class of compounds with potential biological activities.

Spirocyclopentaneoxindole derivatives containing four consecutive stereocenters, including a spiro quaternary center, were constructed by an organocatalytic iminium-enamine cascade sequence in good yields (up to 86%) with excellent enantiomeric (up to >99% ee) and diastereomeric purities (up to >99:1dr). This highly efficient procedure will allow diversity-oriented syntheses of this intriguing class of compounds with potential biological activities.

A new series of bipyridine ligands coupled with Cinchona alkaloids were prepared in relatively high yields in only one step starting from commercially or readily available materials, and have been developed as chiral ligands for copper(II)-catalyzed asymmetric Henry reactions. The catalytic system works well with a wide range of aromatic, aliphatic, and heteroaromatic aldehydes to afford the corresponding nitroalkanols with high enantioselectivity (up to 92%) in good yields (up to 89%). A transition state model was proposed based on H-1 NMR spectroscopy, X-ray structure, and computational calculations. (C) 2013 Elsevier Ltd. All rights reserved.

Polystyrene-immobilized DABCO was used for the first time as a basic organocatalyst for carbon-carbon bond formation reactions. The supported catalyst could be used as a reusable catalyst in the Knoevenagel condensation of a wide range of aromatic/heterocyclic/alpha,beta-unsaturated aldehydes and ketones with active methylene compounds. The reaction conditions are mild and the method is operationally simple. The reactions proceed in a short time period and with 100% selectivity. The catalyst could be easily separated from the reaction by filtration and recycled ten times without activity loss. Based on the catalyst, a continuous flow process was also developed.

Phthalimide derivatives as nitrogen nucleophiles with ,-unsaturated aldehydes for asymmetric aza-Michael additions have been reported. The reactions proceed smoothly to afford corresponding Michael adducts in good yields (up to 98%) and enantioselectivities (up to 95% ee).

Two new C 1 -symmetric primary-secondary diamines were synthesized via the reaction of ( S,S )-1,2-diphenyl ethylene diamine with 3,5-ditert-butyl salicylaldehyde and salicylaldehyde, respectively, followed by reduction with NaBH 4 . The combination of the ligand from 3,5-ditert-butyl salicylaldehyde with CuBr could effciently catalyze the Henry reaction to afford β -nitroalkanols in moderate to good yields (up to 87%) and high enantioselectivities (up to 88% ee ). A possible mechanism of the reaction was proposed.

AbstractFor the first time the highly enantioselective title reaction using a readily available chiral catalyst is developed.

Novel bipyridine substituted cinchona ligands are prepared and successfully applied to Cu(II)-catalyzed asymmetric Henry reactions.

The first application of 4-nitrophthalimide as nitrogen nucleophile for enantioselective aza-Michael addition to nitroalkenes has been developed. The process is promoted by chiral thiourea catalyst derived from cinchonine to give corresponding Michael adducts with up to 87% ee. Activity test showed that some products of the reaction have moderate or good herbicidal activity against cole and barnyard grass at 100 mu g/ml. (C) 2013 Elsevier Ltd. All rights reserved.

The first highly enantioselective aza-Michael addition reactions of 4-nitrophthalimide with α,β-unsaturated ketones have been reported. The reactions gave the corresponding Michael adducts in moderate to good yields (49–98%) and excellent enantioselectivities (95–>99% ee). Computational studies demonstrate that the reason why 4-nitrophthalimide acts as a suitable nucleophile may be because it is more easily activated and therefore it has a stronger nucleophilicity.

A class of chiral ligands has been developed by combining phenanthroline with quinine in a one-step method that does not require resolution. The synthesized three ligands were then coordinated with Cu(II) and the performance of the resultant chiral catalysts in the asymmetric Henry reaction was evaluated. Moderate to good yields (up to 86%) with high enantioselectivities (up to 99% ee) were observed in the reactions catalyzed by one of the three catalysts. Theoretical calculations were performed to analyze the catalytic activities of the different Cu(II)-ligand catalysts. Three different ligands were investigated and one ligand was found to adopt an unexpected five-coordinated mode; the second coordinated with two nitrogen atoms of phenanthroline to give a complex, which activated both substrates of Henry reaction; the third was unable to form a complex with Cu(II).

A C(2)-symmetric tetraamine catalyst was developed for the asymmetric Michael addition of ketones to chalcones. The corresponding adducts 1,5-dicarbonyl compounds were obtained in good chemical yields with high levels of diastereo- and enantioselectivities (up to >99 : 1 dr and 93% ee) under mild conditions. By studying the ESI-MS of the intermediates, a proposed mechanism was disclosed.

C2-Symmetric pyrrolidine-based tetraamine, available from commercially starting materials, showed good cata- lytic activity for asymmetric Michael additions of ketones to nitroalkenes especially to chalcones. The reactions proceeded to give the corresponding products in good yields and in a highly selective manner.

The first organocatalytic enantioselective aza-Michael addition of purine bases to α,β-unsaturated ketones has been developed, affording Michael adducts in moderate to high yields (up to 96% yield) and high to excellent enantioselectivities (up to >99% ee). A wide range of α,β-unsaturated ketones including aliphatic and aromatic enones are tolerated in this process, generally demonstrating good reactivity, regioselectivity and enantioselectivity. The aromatic α,β-unsaturated ketones showing quite low reactivity in the reported catalytic systems, were first successfully employed as Michael acceptors in this transformation, yielding high enantioselectivities (up to 94% ee). The utility of this method was also applied for the synthesis of enantioenriched non-natural nucleoside analogues with potential biological activities.

Several chiral primary amines were introduced as organocatalysts for the asymmetric Biginelli reaction. The reaction was performed by using a combined catalyst consisting of a chiral bifunctional primary amine–pyridine 5j and hydrochloric acid in a mixed solvent of 1,4-dioxane/CHCl3 (8/2, v/v) at room temperature. The corresponding dihydropyrimidines were obtained in moderate to high yields with up to >99% ee under mild conditions.

A highly efficient catalytic system composed of a simple and commercially available chiral primary diamine (1R,2R)-cyclohexane-1,2-diamine(6) and trifluoroacetic acid(TFA) was employed for asymmetric Aldol reaction in i-PrOH at room temperature. A loading of 10%(molar fraction) catalyst 6 with TFA as a cocatalyst could catalyze the Aldol reactions of various ketones or aldehydes with a series of aromatic aldehydes, furnishing Aldol products in moderate to high yields(up to >99%) with enantioselectivities of up to >99% and diastereoselectivities of up to 99:1.

Bispirooxindole derivatives containing three stereocenters, including two spiro quaternary centers, were synthesized in a high-yielding, atypically rapid, and stereocontrolled cascade Michaelcyclization reaction between methyleneindolinones and isothiocyanato oxindoles catalyzed by a bi- or multifunctional organocatalyst. Mild conditions were used to construct bispirooxindoles with excellent enantio- and diastereomeric purities within less than 1 min. Catalyst reconfiguration offered access to the opposite enantiomer. This exceptionally highly efficient procedure will allow diversity-oriented syntheses of this intriguing class of compounds with potential biological activities.

AbstractThe catalyst and the solvent can be recycled and reused for at least five times without significant loss of activity and stereoselectivity.