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A primary amine-catalyzed asymmetric formal aza-Diels-Alder reaction of trifluoromethyl hemiaminals with enones was developed via a chiral gem-diamine intermediate. This novel protocol allowed facile access to structurally diverse trifluoromethyl-substituted piperidine scaffolds with high stereoselectivity. The utility of this method was further(More)
The highly enantioselective Friedel-Crafts alkylation of pyrrole with isatins catalyzed by the tridentate Schiff base/Cu catalyst was developed. Hexafluoroisopropanol (HFIP) was used as a crucial additive to improve the enantioselectivity. In the case of N-unprotected isatins, an innovative substrate slow-releasing strategy was applied by virtue of a(More)
One common hypothesis is that wind can affect concentrations of nutrients (i.e., nitrogen and phosphorus) and chlorophyll-a (Chl-a) in shallow lakes. However, the tests of this hypothesis have yet to be conclusive in existing literature. The objective of this study was to use long-term data to examine how wind direction and wind speed affect the(More)
A general organocatalytic asymmetric dehydrated Mannich reaction of fluoroalkyl hemiaminals with ketones is reported. In this Mannich reaction, previously less explored aryl ketones showed great reactivity. By virtue of this efficient method, a wide range of biologically active β-amino ketones were directly obtained. More importantly, two different(More)
The highly enantioselective hetero-Diels-Alder reaction of Danishefsky's diene with glyoxals was developed by virtue of a readily accessible chiral copper catalyst. This efficient transformation provided a facile and scalable access to a wide range of biologically active dihydropyrones with a high level of enantioselectivities. Moreover, the substrate scope(More)
A bifunctional amino sulfonohydrazide which contains multiple sites for hydrogen bonding with substrates was found to enhance reactivity and enantioselectivity in the direct asymmetric Mannich reaction of N-sulfonyl cyclic ketimines with ketones. In this efficient transformation, not only methyl ketones but also cyclic ketones can be employed to provide a(More)
A highly enantioselective hetero-Diels-Alder reaction of Danishefsky's diene with β,γ-unsaturated α-ketoesters was developed for the first time by virtue of chiral copper complexes. This protocol provided a facile access to optically active dihydropyranones bearing a quaternary center with high enantioselectivities and good yields. Furthermore, on the basis(More)
A Friedel-Crafts alkylation of pyrrole was developed to afford the β,γ-unsaturated α-hydroxy esters bearing a quaternary stereogenic center with good enantioselectivities and yields. This protocol represents the first report of 1,2-addition of Friedel-Crafts alkylation of pyrrole to β,γ-unsaturated α-ketoesters.