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ABSTRACT: An unprecedented Ag(I)-catalyzed asymmetric desymmetrization of spiro cyclohexadienone lactones has been developed successfully, which performs well over a broad scope of substrates and provides a facile access to optically active spirolactone-pyrrolidines in high yields with excellent levels of diastereo-/enantioselectivities.
Organic Letters 04/2013; · 5.86 Impact Factor
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ABSTRACT: Pyrrole into one: The catalytic asymmetric 1,3-dipolar cycloaddition of cyclic aldimino esters has been accomplished for the first time, enabling facile access to spiro(butyrolactonepyrrolidines) containing one spiro quaternary center and three tertiary stereogenic centers (see scheme). The catalytic system performs well with a broad range of substrates, furnishing synthetically useful adducts in high yields, with excellent diastereo- and enantioselectivities under mild conditions.
Chemistry 06/2012; 18(26):8042-6. · 5.93 Impact Factor
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ABSTRACT: An efficient protocol for the direct construction of bioactive thiochromanes was developed via a catalytic asymmetric cascade sulfa-Michael-aldol reaction of 2-mercaptobenzaldehyde with α,β-unsaturated N-acyl imides. The key to the present methodology is introducing a pyrazole moiety as H-bond acceptor, which allowed for better organization and activation and hence higher enantioselectivity.
Chemical Communications 05/2012; 48(58):7238-40. · 6.17 Impact Factor
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Chemistry 11/2011; 17(46):12922-7. · 5.93 Impact Factor
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ABSTRACT: A direct and facile access to enantioenriched pyroglutamate derivatives bearing a unique quaternary stereogenic center has been developed via Cu(I)/BINAP-catalyzed tandem Michael addition-elimination of α-substituted aldimino esters with Morita-Baylis-Hillman (MBH) carbonates followed by a deprotection/lactamization protocol, which performs well over a broad scope of substrates and provides biologically active pyroglutamate derivatives in good yields and excellent enantioselectivities.
Organic Letters 09/2011; 13(20):5600-3. · 5.86 Impact Factor
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ABSTRACT: Trifluoromethylated pyrrolidines have been synthesized via catalytic asymmetric 1,3-dipolar cycloaddition with excellent stereoselectivity for the first time. Epimerization of the endo-pyrrolidines obtained from cis-4,4,4-trifluorocrotonate into the exo-pyrrolidines was also revealed.
Chemical Communications 09/2011; 47(39):11110-2. · 6.17 Impact Factor
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ABSTRACT: A novel catalytic asymmetric Michael addition of azomethine ylide with β-substituted alkylidene bisphosphates was realized in the presence of a chiral copper(I)/TF-BiphamPhos complex. The present system provides a unique and facile access to enantioenriched unnatural α-amino acid derivatives containing gem-bisphosphonates (gem-BPs) in high yields with excellent diastereoselectivities and enantioselectivities. Subsequent transformations lead to the expedient preparation of biologically active unnatural α-amino acid derivatives containing BPs and bisphosphonic acids without loss of diastereo- and enantiomeric excess.
Journal of the American Chemical Society 06/2011; 133(30):11757-65. · 9.91 Impact Factor
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ABSTRACT: The first catalytic asymmetric 1,3-dipolar cycloaddition of azomethine ylides with easily accessible Morita-Baylis-Hillman adducts as the dipolarophiles has been developed successfully and provides the highly substituted pyrrolidines bearing a unique quaternary and two tertiary stereogenic centers in excellent diastereoselectivity and up to 97% ee.
Chemical Communications 05/2011; 47(19):5494-6. · 6.17 Impact Factor
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ABSTRACT: A direct and facile synthesis of highly functional 5-aza-spiro[2,4]heptanes, a valuable structural motif for drug discovery, is developed via catalytic asymmetric 1,3-dipolar cycloaddition of cyclopropylidene acetate and azomethine ylides for the first time.
Chemical Communications 03/2011; 47(9):2616-8. · 6.17 Impact Factor
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ABSTRACT: Asymmetric 1,3-dipolar cycloaddition of N-unprotected 2-oxoindolin-3-ylidene with azomethine ylides for the construction of spirooxindole-pyrrolidines bearing four contiguous stereogenic centers has been achieved with AgOAc/TF-BiphamPhos complexes for the first time. This catalytic system performance well over a broad scope of substrates, providing the synthetically useful adducts in high yields and excellent diastereoselectivities and moderate enantioselectivities.
Organic & Biomolecular Chemistry 01/2011; 9(6):1980-6. · 3.70 Impact Factor
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ABSTRACT: The first asymmetric Michael addition of alpha-aryl cyclopentanones to nitroolefins for construction of adjacent quaternary and tertiary stereocenters has been achieved with excellent diastereo-/enantioselectivity.
Chemical Communications 09/2010; 46(36):6840-2. · 6.17 Impact Factor
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ABSTRACT: The first exo-selective asymmetric 1,3-dipolar cycloaddition of alkylidene malonates with azomethine ylides catalyzed by AgOAc/TF-BiphamPhos has been reported in good yields and good to excellent enantio-/diastereoselectivities.
Chemical Communications 03/2010; 46(10):1727-9. · 6.17 Impact Factor
