We report conditions for the preparation of a range of trifluoromethylated isoxazole building blocks through the cycloaddition reaction of trifluoromethyl nitrile oxide. It was found that controlling the rate (and therefore concentration) of the formation of the trifluoromethyl nitrile oxide was Critical for the preferential formation of the desired isoxazole products versus the furoxan dimer. Different conditions were optimised for both aryl- and alkyl-substituted alkynes. In addition, the reactivity at the isoxazole 4-position has been briefly explored for these building blocks. Conditions for intermolecular C-H arylation, lithiation and electrophile quench, and alkoxylation were all identified with brief substrate scoping that signifies useful tolerance to a range of functionalities. Finally, complementary processes for structural diversification through either intramolecular cyclisation or intermolecular cross-coupling were developed.

We describe a new synthesis of diospogin A, its enantiomer ent-diospongin A and C-5 epimer of diospongin B from commercially available tri-O-acetyl-D-glucal, based on a copper catalyzed Michael addition of phenyllitium to the corresponding ,-unsaturated ketone. The stereochemical course of the Michael addition was unambiguously established by X-ray crystallographic analysis.

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, 5 -D i s u b s t i t u t e d 3 -O x y g e n a t e d T e t r a h y d r o f u r a n sAbstract: The synthesis of enantiomerically pure 2,5-disubstituted 3-oxygenated tetrahydrofurans has been achieved from cheap and commercially available L-malic acid. This method was used to prepare an advanced intermediate toward CMI-977, a promising candidate for the treatment of chronic asthma.