Two attractive chirons, aldehyde 6 and chloride 7, exhibiting functionalized ent-spongiane-type tricyclic skeletons (ABC ring system), have been constructed and their absolute configurations have been studied by NMR spectroscopy and confirmed by single-crystal X-ray diffraction. Both of these chirons are derived from commercially available andrographolide in good yield. Aldehyde 6 is obtained through a novel K₂S₂O₈-catalyzed aquatic ring-closing reaction of allylic sodium sulfonate and intramolecular 1,7-hydrogen atom transfer process. Further mechanistic investigations demonstrate that the 1,7-hydrogen atom transfer is a free-radical process, whereby hydrogen migrates from C18 to C17, as evidenced by double-18- deuterium-labeled isotope experiments. Prospective applications of these two chiral sources are also discussed.

Microtuning of the enzyme active pocket has led to a smart library of epoxide hydrolase variants with an expanded substrate spectrum covering a series of typical β-blocker precursors. Improved activities of 6- to 430-fold were achieved by redesigning the active site at two predicted hot spots. This study represents a breakthrough in protein engineering of epoxide hydrolases and resulted in enhanced activity toward bulky substrates.

This paper describes a concise and practical route to enantiomerically enriched 5-alkyl substituted nicotine analogs. The Vilsmeier reaction was used to construct the nicotinaldehydes ring followed by the introduction of the chiral homoallylic alcohol by organic boron reagent and the cyclization of the pyrrolidine ring through the reduction of a chiral azide. 17 analogs have been synthesized and their corresponding biological activities were tested, in which compounds 10d and 10g exhibit excellent IC₅₀ values against RD and SY-SY5Y.

This paper describes a rapid and practical synthetic route involving six-step reactions towards the diastereoselectively synthesis of (±)-endo-Epibatidine, starting from 6-chloro-3-pyridinecarboxaldehye. The effective Henry reaction gave precursor (E)-6-(6-chloropyridin-3-yl)-5-nitrohex-5-en-2-one (3a) which could be used in the next step. Various benzoic acid derivatives were used to optimize intramolecular Michael addition of ketone to pyridinylnitroolefins to provide the key intermediate 3-(6-chloropyridin-3-yl)-4-nitrocyclohexanone ((±)-7a) with high yield.