[show abstract][hide abstract] ABSTRACT: Simple and readily available chiral N-(sulfinyl)allylamines have been developed as efficient novel ligands for the rhodium-catalyzed enantioselective 1,2-addition of arylboronic acids to challenging aliphatic α-ketoesters. By employing the linear or branched sulfinamide-olefin ligands, interesting enantioselectivity as well as regioselectiv-ity reversal in the related asymmetric additions were observed.
Chinese Journal of Chemistry 03/2013; 2013(31):321. · 0.92 Impact Factor
[show abstract][hide abstract] ABSTRACT: The kinetic characteristics of hydroxamate-based inhibitors of matrix metalloproteinase (MMP)-12 were explored using an SPR biosensor-based assay and enzyme inhibition analysis. These high-affinity inhibitors were shown to dissociate very slowly from the enzyme–inhibitor complex while a carboxylate analogue had a much faster dissociation rate, verifying the importance of the hydroxamate group for the slow dissociation. Progress curve enzyme inhibition analysis confirmed that the hydroxamate compounds but not the carboxylate compound acted as time-dependent inhibitors. The slow dissociation excluded steady-state estimation of IC50-values and Ki values but also made Ki values from progress curve analysis unreliable. Although a full characterization of the inhibitors using biosensor analysis was limited by slow dissociation, it provided kinetic and mechanistic information of relevance for MMP drug discovery and avoided some pitfalls of conventional enzyme inhibition assays.
Medicinal Chemistry Communication 01/2013; 4(2):432-442. · 2.72 Impact Factor
[show abstract][hide abstract] ABSTRACT: Room temperature zinc-mediated diastereoselective allylation or propargylation of isatin-derived N-tert-butanesulfinyl ketimines for synthesis of highly enantiomerically enriched tetrasubstituted 3-aminooxindoles is described.
Chemical Communications 01/2013; · 6.38 Impact Factor
[show abstract][hide abstract] ABSTRACT: SIRT1 is a NAD(+)-dependent deacetylase. Here we described new SIRT1 inhibitors with the scaffold of benzofuran-3-yl(phenyl)methanone. The inhibitors were predicted to bind in C-pocket of SIRT1, forming hydrophobic interactions with Phe273, Phe312 and Ile347. Introducing hydroxyl to meta position of phenyl may form H-bond with Asn346. Indeed, (2,5-dihydroxyphenyl)(5-hydroxy-1-benzofuran-3-yl)methanone (16), an analogue with hydroxyls at ortho and meta positions, showed greater inhibition. The binding mode was validated by structural modifications and kinetic studies. Since C-pocket is the site where the nicotinamide moiety of NAD(+) binds and the hydrolysis takes place, binding of 16 in C-pocket would block the transformation of NAD(+) to productive conformation and hence inhibit the deacetylase activity. Consistently, 16 inhibited SIRT1 through up-regulating p53 acetylation on cellular level.
European journal of medicinal chemistry 12/2012; 60C:441-450. · 3.27 Impact Factor
[show abstract][hide abstract] ABSTRACT: The domino effect: An efficient and general catalytic one-pot synthesis of quaternary-substituted isochroman derivatives has been developed. The cascade transformation relies on rhodium-catalyzed highly regio- and enantioselective 1,2-addition of arylboronic acids to unsymmetrical α-diketones and intramolecular etherification or esterification, and provides a variety of enantioenriched isochromanones under exceptionally mild conditions.
[show abstract][hide abstract] ABSTRACT: The first example of catalytic asymmetric 1,2-addition of arylboronic acids to heteroaryl α-ketoesters has been developed for the highly efficient and enantioselective synthesis of quaternary carbon-containing heteroaromatic α-hydroxy esters. The reaction works well with a variety of α-ketoesters including 3-indoleglyoxylates, 3-benzofuranglyoxylates and 3-benzothiopheneglyoxylates under very mild conditions, affording the corresponding products in moderate to good yields with high enantiomeric excesses (up to 97%).
[show abstract][hide abstract] ABSTRACT: A pincer-like chiral auxiliary strategy for synthesizing various optically active α,α-disubstituted amino acids in high yields with excellent enantioselectivities is described.
Chemical Communications 06/2012; 48(58):7274-6. · 6.38 Impact Factor
[show abstract][hide abstract] ABSTRACT: The design and development of an extraordinarily interesting new class of chiral sulfur-olefin hybrid ligands with remarkable structural simplicity were described. These unique sulfinamide-olefin ligands have been proved to be highly effective ligands in rhodium-catalyzed asymmetric 1,4-addition reactions of aryl boronic acids to α,β-unsaturated carbonyl compounds (up to 99% yield and 98% ee).
[show abstract][hide abstract] ABSTRACT: Lewis acid-catalyzed highly diastereoselective asymmetric Friedel-Crafts alkylation of arenes with a chiral N-tert-butanesulfinylimino ester is described. The reaction can be accomplished with ease in the presence of a catalytic amount of In(OTf)(3) at room temperature, providing a series of enantiomerically enriched α-arylglycines in good yields and with excellent diastereoselectivities (up to 99% de). Highly stereoselective double Friedel-Crafts alkylation to afford dialkylation product was also investigated.
[show abstract][hide abstract] ABSTRACT: Simply the best: The title reaction has been achieved by asymmetric rhodium catalysis employing an extremely simple, chiral N-(sulfinyl)cinnamylamine ligand. A variety of highly enantioenriched, tertiary α-hydroxy carbonyl derivatives were easily accessed at room temperature under mild conditions with enantioselectivities of up to 99 %.
Angewandte Chemie International Edition 12/2011; 51(3):780-3. · 13.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Here we show that simple and readily available chiral sulfinamide-olefins can display great catalytic activities and enantioselectivities in rhodium-catalyzed 1,4-addition reactions. This study represent the first example of chiral sulfur-based olefin ligand class for transition metal-catalyzed asymmetric transformation.
Chemical Communications 07/2011; 47(25):7230-2. · 6.38 Impact Factor
[show abstract][hide abstract] ABSTRACT: The design and development of a novel class of chiral sulfur-olefin hybrid ligands with high synthetic feasibility are described. These new sulfoxide-olefin ligands showed excellent catalytic activities and enantioselectivities (up to 98% ee) in rhodium-catalyzed asymmetric 1,4-addition reactions of aryl boronic acids to α,β-unsaturated carbonyl compounds.
[show abstract][hide abstract] ABSTRACT: The novel bifunctional bisalkaloids have been developed as highly efficient catalysts for the asymmetric conjugate addition of 1,3-dicarbonyl compounds to nitroalkenes with low catalyst loading (1 mol %) at ambient temperature, providing the products with excellent enantioselectivities (up to 97% ee).
[show abstract][hide abstract] ABSTRACT: The first palladium-diene-catalyzed asymmetric Suzuki-Miyaura coupling reaction has been achieved. A number of functionalized biaryls were obtained in high yields and in moderate to high enantioselectivities. The existence of an ortho-formyl group greatly improves the catalyst efficiency and permits further synthetic elaborations.
[show abstract][hide abstract] ABSTRACT: An efficient one-pot asymmetric synthesis of highly substituted γ-lactams containing α-methylene groups has been successfully developed. A wide range of γ-lactams could be obtained in high yields with excellent diastereomeric ratios of up to 99:1 in favor of trans isomers. In particular, excellent enantioselectivities of the two newly formed stereogenic centers with up to 99% ee were observed.
[show abstract][hide abstract] ABSTRACT: An extremely mild and practical approach for the preparation of enantiomerically enriched β-aryl substituted homoallylic amines bearing two adjacent stereogenic centers was realized by room temperature zinc-mediated highly stereoselective cinnamylation of N-sulfinyl imines.
Chemical Communications 10/2010; 46(44):8460-2. · 6.38 Impact Factor
[show abstract][hide abstract] ABSTRACT: A novel and rapid assembly of an interesting class of furocoumarins-4H-furo[3,2-c]chromen-4-ones has been successfully achieved using one-pot sequential coupling/cyclization strategy with easily available starting materials 3-bromo-4-acetoxycoumarins and terminal alkynes. The key synthesis involves Pd/Cu-catalyzed alkynylation with in situ prepared dialkynylzincs followed by intramolecular hydroalkoxylation.