4-Alkoxycarbonyl- and aminocarbonyl-substituted isoxazoles as masked acrylates and acrylamides in the asymmetric synthesis of delta2-isoxazolines.

4-Alkoxycarbonyl and aminocarbonyl-substituted isoxazoles undergo conjugate reduction to give delta2-isoxazolines on treatment with sodium borohydride and sodium trifluoroacetoxyborohydride, respectively. They are also alkylated at C5 through sonication with secondary and tertiary alkyl iodides in the presence of zinc dust and copper(I) iodide. These reactions are analogous to those observed with acrylates and acrylamides.

Efficient batch and continuous flow Suzuki cross-coupling reactions under mild conditions, catalysed by polyurea-encapsulated palladium (II) acetate and tetra-n-butylammonium salts.

Suzuki cross-coupling reactions are effected in both conventional organic solvents, under continuous flow conditions at 70 degree C, and in batch mode in supercritical carbon dioxide (scCO2), at temperatures as low as 40 degrees C in the presence of palladium(II) acetate microencapsulated in polyurea [PdEnCat] and tetra-n-butylammonium salts.

Nitrile oxide cycloadditions in supercritical carbon dioxide.

The regioselectivity of dipolar cycloadditions of mesitonitrile oxide to various dipolarophiles in supercritical carbon dioxide can be tuned by changes in density, the magnesium bromide-mediated cycloaddition to pent-1-en-3-ol proceeding with higher stereoselectivity than in most conventional solvents.