Synthesis of Optically Active Organofluorides by Ring Opening of Oxazolidinone-Fused Aziridines.

A general method for synthesizing optically active, primary, secondary, and tertiary organofluorides was developed. This chiral pool synthesis utilized the skeleton of arabinose to generate diastereomerically pure 2-oxazolidinone-fused aziridines, which underwent ring opening with a fluoride anion. The adducts, polyoxygenated organofluorides, were useful precursors to various fluorinated compounds, such as fluorinated amino acids.

Synthesis of Methyl l-Kijanosides by Regio- and Stereoselective Ring Opening of 2-OxazolidinoneFused Aziridines.

Kijanose is one of the most highly functionalized deoxysugars found in nature and a challenging synthetic target. We found that the ring opening of trisubstituted, 2-oxazolidinone-fused aziridines is regio- and stereoselective, and the azide adduct has the same stereochemistry as that of kijanose after converting the azido to a nitro group. Therefore, both α- and β-methyl l-kijanosides were prepared from ethyl l-lactate in 14% total yield.

Synthesis of Natural (-)-Antrocin and its Enantiomer via Stereoselective Aldol Reaction.

The total synthesis of (-)-antrocin and its enantiomer are presented. Antrocin (-)- is an important natural product which acts as an antiproliferative agent in a metastatic breast cancer cell line (IC: 0.6 M).

Radical Reactions in Cavitands Unveil the Effects of Affinity on Dynamic Supramolecular Systems.

Radical reduction of alkyl halides and aerobic oxidation of alkyl aromatics are reported using water-soluble container compounds ( and ). The reductions involve α,ω-dihalides (- and ) with radical initiators in cavitand hosts with varied binding affinities. Product distributions lead to general guidelines for the use of dynamic supramolecular systems with fast reactions.

Binding orientation and reactivity of alkyl α,ω-dibromides in water-soluble cavitands.

Host-guest complexation of long chain α,ω-dibromides was evaluated in deep water-soluble cavitands 1 and 2. The bound dibromides (C7-C12) tumble rapidly on the NMR timescale and averaged signals were observed. The complexation allows mono hydrolysis of dibromides in aqueous solution.

Pharmacological activities of antroquinonol- Mini review.

Antrodia camphorata is an expensive mushroom that grows on the inner cavity of an endangered native tree of Taiwan namely Cinnamomum kanehirai Hayata. It is used as a traditional medicine in Taiwan and has several health benefits including free radical scavenging, anti-inflammatory, antimicrobial, hepatoprotective, neuroprotective, antidiabetic, and free radical-induced DNA damage protecting activities. Antroquinonol is a tetrahydro ubiquinone derivative found predominately in the mycelium of Antrodia camphorata, and is characterized by numerous biological and pharmacological activities.

Anti-addition of Dimethylsulfoxonium Methylide to Acyclic α,β-Unsaturated Ketones and Its Application in Formal Synthesis of an Eicosanoid.

Cyclopropanation using dimethylsulfoxonium methylide (Corey-Chaykovsky reaction) was examined with a series of linear α,β-unsaturated ketones, and the results showed that the major trajectory for the addition of the sulfur ylide to the enones is anti, related to the γ-substituent. The stereochemical assignment for the generated cyclopropanes was achieved by X-ray crystallography or comparing with the reported spectroscopic data. We found that the diastereoselectivity was influenced by several factors, including the protecting groups, solvents, and temperatures, and good anti/syn ratios (>10:1) were often obtained using the -butyldimethylsilyl and -butyldiphenylsilyl-protected substrates.