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Tainan, Taiwan

The stereoselective arylation of hydroxy protected 1,6-anhydro-β-d-glucose with arylalanes to provide β-C-arylglucosides is reported. Modification of triarylalanes, Ar3Al, with strong Brønsted acids (HX) or AlCl3 produced more reactive arylating agents, Ar2AlX, while the incorporation of alkyl dummy ligands into the arylating agents was also viable. Me3Al and i-Bu2AlH were found useful in the in situ blocking of the C3-hydroxyl group of 2,4-di-O-TBDPS protected 1,6-anhydroglucose. The utility of the method was demonstrated by the synthesis of the SGLT2 inhibitor, canagliflozin. © 2015 American Chemical Society. Source


Gopula B.,National Taiwan Normal University | Yang S.-H.,National Taiwan Normal University | Kuo T.-S.,National Taiwan Normal University | Hsieh J.-C.,Tamkang University | And 3 more authors.
Chemistry - A European Journal | Year: 2015

Chiral rhodium catalysts comprising 2,5-diaryl- substituted bicyclo[2.2.1]diene ligands L1-L10 were utilized in the enantioselective 1,4-addition reaction of arylboronic acids to N-substituted maleimides. In the presence of 2.5mol % of RhI/L2, enantioenriched conjugate addition adducts were isolated in 72-99 % yields with 86-98 %ee. This protocol offers a convenient method to access a variety of 3-arylsuccinimides in a highly enantioselective manner. Maleimides with readily cleavable N-protecting groups were tolerated enabling the synthesis of useful synthetic intermediates. Pyrrolidine 4, a biologically active compound, and pyrrolidine 5, an ent-precursor to an HSD-1 inhibitor, were synthesized to demonstrate the utility of this method. The road to rhodium! Enantioselective conjugate addition of a range of arylboronic acids to variously N-substituted maleimides, catalyzed by RhI complexes prepared in situ using chiral bicyclo[2.2.1]diene ligands, afforded the corresponding 3-arylsuccinimides with up to 98 %ee at 50 C (see scheme). © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Chen C.-C.,National Taiwan Normal University | Gopula B.,National Taiwan Normal University | Syu J.-F.,National Taiwan Normal University | Pan J.-H.,National Taiwan Normal University | And 4 more authors.
Journal of Organic Chemistry | Year: 2014

Enantiomerically enriched tosyl-protected diarylmethylamines were rapidly prepared by the asymmetric addition of arylboronic acids to N-tosylaldimines under mild conditions in the presence of a catalyst prepared in situ from Rh(I) and a chiral diene ligand. This methodology offers access to diarylmethylamines in good yields with excellent chiral purity at room temperature using MeOH as a solvent and NEt3 as a base. Its synthetic utility was demonstrated by the preparation of (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline (14), an antagonist of the N-methyl-d-aspartate (NMDA) receptor. © 2014 American Chemical Society. Source


Gopula B.,National Taiwan Normal University | Tsai Y.-F.,National Taiwan Normal University | Kuo T.-S.,National Taiwan Normal University | Wu P.-Y.,ScinoPharm Taiwan | And 2 more authors.
Organic Letters | Year: 2015

The asymmetric conjugate addition of arylboronic acids to substituted and unsubstituted β-pyrazol-1-yl (E)-tert-butyl acrylates 4 catalyzed by 5 mol % of the Rh(I)/diene 2a catalyst provided the corresponding addition products in 44-98% yield and 91->99.5% ee. The method was applied to the formal synthesis of (3S)-3-aryl-3-(pyrazol-1-yl)propanoic acid 1b with agonistic activity toward the human GPR40 G-protein coupled receptor. © 2015 American Chemical Society. Source


Huang K.-C.,National Taiwan Normal University | Gopula B.,National Taiwan Normal University | Kuo T.-S.,National Taiwan Normal University | Chiang C.-W.,National Taiwan Normal University | And 3 more authors.
Organic Letters | Year: 2013

An efficient enantioselective addition of an array of arylboronic acids to various β-nitrostyrenes catalyzed by a novel and reactive rhodium-diene catalyst (S/C up to 1000) was developed, providing β,β- diarylnitroethanes in good to high yields (62-99%) with excellent enantioselectivities (85-97% ee). The method was extended to 2-heteroarylnitroolefins and 2-alkylnitroolefins similarly providing the desired products with high enantioselectivities and yields. The usefulness of this method was demonstrated in the formal synthesis of the enantiomer of the dopamine receptor agonist and antagonist, SKF 38393. © 2013 American Chemical Society. Source

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