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Catalytic asymmetric dearomative [3+2] cycloaddition of α-imino γ-lactones with either 3-nitroindoles or 2-nitrobenzofurans by using a chiral copper complex as the catalyst was developed. A wide range of structurally diverse polyheterocyclic compounds containing spirocyclic-fused butyrolactone-pyrrolidine-indoline and butyrolactone–pyrrolidine–dihydrobenzofuran skeletons could be smoothly obtained with excellent results (>99:1 dr and 98% ee). The potential synthetic applications of this methodology were also demonstrated by the scale-up experiment and by the diverse transformations of one product. This method is characterized by high asymmetric induction, wide functional group tolerance and scalability, and attractive product diversification. [ABSTRACT FROM AUTHOR]

An organocatalytic enantioselective decarboxylative Mannich reaction of pyrazolin‐5‐one derived ketimines with β‐ketoacids using quinine‐derived bifunctional squaramide as a catalyst has been developed. With the developed protocol, a series of chiral β‐amino ketone‐pyrazolinone derivatives were obtained in excellent yields (up to 99 %) with good enantioselectivities (up to 94:6 er). The enantioselective decarboxylative aldol reaction of pyrazole‐4,5‐dione with β‐ketoacids was also realized under the standard reaction conditions. [ABSTRACT FROM AUTHOR]

Abstract: An efficient asymmetric dearomative [3+2] cycloaddition reaction of 2‐nitroindoles and 2‐nitrobenzothiophenes with 3‐isothiocyanato oxindoles was developed by using a chiral Zn(OTf)2/bis(oxazoline) complex as a catalyst. With the developed protocol, a range of enantioenriched complex heterocyclic compounds containing three contiguous stereocenters, one of which is spirocyclic center, could be obtained in quantitative yields with excellent diastereo‐ and enantioselectivities. The potential utility of this method was showcased by the diverse transformations of the products. [ABSTRACT FROM AUTHOR]

Abstract: A highly diastereo‐ and enantioselective dearomative [3+2] cycloaddition reaction of 3‐nitrobenzothiophenes and 3‐nitrothieno[2,3‐b]with 3‐isothiocyanato oxindoles is developed. The reaction is catalyzed by the chiral Zn(OTf)2/bis(oxazoline, and is the second example of a catalytic asymmetric dearomative cycloaddition reaction of 3‐nitrobenzothiophene derivatives. A range of complex heterocyclic compounds containing three contiguous stereocenters, one of which is spirocyclic center, can be obtained in quantitative yields with excellent stereoselectivities. [ABSTRACT FROM AUTHOR]

Lewis-base-catalyzed asymmetric hydrosilylation of substituted benzophenone N-aryl imines was investigated. Among various chiral Lewis-base catalysts, a catalyst derived from L-Serine was found to be the most favorable one which promote the reaction to afford a series of (diarylmethyl)amines with high yields (up to 97 %) in moderate to good enantioselectivities (up to 97 % ee). The absolute configuration of the product was determined by the X-ray crystallographic analysis. [ABSTRACT FROM AUTHOR]

The Lewis base-organocatalyzed asymmetric hydrosilylation of α-acetamido-β-enamino esters was investigated. Among various chiral Lewis base catalysts, a novel catalyst derived from L-serine was found to be the most efficient one which can promote the reaction to afford a series of α,β-diamino acid derivatives with high yields (up to 99%), excellent enantioselectivities (up to 98% ee) and moderate diastereoselectivities (up to 80:20 dr). The absolute configuration of one of the products was determined by the X-ray crystallographic analysis. In addition, the mechanism and the transition state of the reaction were proposed. [ABSTRACT FROM AUTHOR]

Cascading catalysis: 3‐Isothiocyanato oxindoles act as powerful and versatile precursors for a range of structurally diverse dispirocyclic thiopyrrolidineoxindoles containing two spiro‐quaternary and three contiguous stereogenic centers in quantitative yields with excellent disatereo‐ and enantioselectivities by only using 1 mol % amino‐thiocarbamate catalyst. [ABSTRACT FROM AUTHOR]

Catalytic asymmetric Michael addition of arylacetyl phosphonates to nitroalkenes was achieved with a chiral bifunctional amine-thiourea bearing a multiple-hydrogen-bond donor as a catalyst. A range of α-substituted carboxylic ester compounds with contiguous tertiary stereocenters could be smoothly obtained in good yields (up to 85%) and with high to excellent diastereo- and enantioselectivities (up to >99:1 dr and 95% ee). The large scale experiment and facile synthesis of a chiral γ-butyrolactam have also been demonstrated. [ABSTRACT FROM AUTHOR]

A range of structurally diverse chiral spiro[imidazolidine-2-thione-4,3′-oxindole] compounds could be obtained via a domino Mannich-cyclization reaction of 3-isothiocyanato oxindoles and imines with commercial quinine as catalyst under mild conditions. The protocol is significantly characterized by simple process, easily available catalyst, high reactivity, low catalyst loading (1 mol %), and good to excellent diastereo- and enantioselectivity (up to>99:1 dr and 97% ee). A plausible dual activation working model was tentatively proposed to account for the stereochemistry of the domino Mannich-cyclization process. [ABSTRACT FROM AUTHOR]

Abstract: An efficient organocatalytic diastereo- and enantioselective method for the construction of spirocyclic oxindole derivatives bearing two spiro quaternary centers and three consecutive stereocenters via a domino Michael/cyclization process has been developed. Using commercially available quinine as catalyst, the reactions of 3-isothiocyanato oxindoles with unsaturated pyrazolones and unsaturated isoxazolones proceeded smoothly under mild reaction conditions for giving two classes of spirocyclic oxindole compounds in high to excellent yields with moderate to good diastereoselectivities and enantioselectivities. A plausible dual activation working model was tentatively proposed to account for the stereochemistry of the domino Michael/cyclization process. [Copyright &y& Elsevier]

Abstract: An effective asymmetric sulfa-Michael addition of various S-nucleophiles to a range of α,β-disubstituted nitroalkenes with bifunctional organocatalyst has been developed. The expected adducts could be obtained in high yields with reasonable diastereo- and enantioselectivities. This process provides an easy access to synthetically useful chiral 1,2-aminothiol derivatives bearing two vicinal stereocenters. Importantly, current work represents the first example about the catalytic asymmetric Michael addition of diverse S-nucleophiles except thioacetic acid to less reactive α,β-disubstituted nitroalkenes. [Copyright &y& Elsevier]

Abstract: A highly efficient method for the construction of a family of spiro[oxazolidine-2-thione-oxindoles] with 3-isothiocyanato oxindoles and aldehydes via a cascade aldol-cyclization process has been developed. This method provides access to spiro[oxazolidine-2-thione-oxindole] derivatives bearing two vicinal quaternary/tertiary stereocenters in up to 95% yield, 98:2 dr, and 89% ee with a chiral bifunctional thiourea–tertiary amine organocatalyst based on DPEN scaffold. Good reactivity was observed and the reaction could be completed within 1.0 min. [Copyright &y& Elsevier]

Abstract: A simple and efficient method for the enantioselective 1,6-Michael addition reaction of anthrone to a series of 3-methyl-4-nitro-5-alkenyl-isoxazoles with a bifunctional thiourea-tertiary amine as catalyst is described. This transformation proceeds smoothly with 10mol% catalyst and provides a series of Michael adducts bearing 3-methyl-4-nitro-isoxazole and anthrone units with good to high enantioselectivities (up to 96% ee) and in very high yields (up to 99%). [Copyright &y& Elsevier]

Abstract: A highly enantioselective aldol reaction of acetaldehyde and a wide scope of isatins has been presented only using readily available 4-hydroxydiarylprolinol as catalyst, affording various desired 3-substituted 3-hydroxyindolin-2-one adducts with moderate to high yield (up to 95%) and good enantioselectivities (up to 98% ee). This method not only represents an example of concise stereoselective synthesis of enantiopure (R)-convolutamydines B and E, but also firstly exhibits expedient asymmetric synthesis optically active (−)-donaxaridine and (R)-chimonamidine. [Copyright &y& Elsevier]