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The application of natural phosphates doped with potassium fluoride as heterogeneous catalysts for the Michael addition of aromatic and aliphatic amines to α,β-unsaturated carbonyl compounds is presented. The natural phosphate catalyst can be regenerated and reused without loss of activity, which makes it an attractive alternative to homogeneous basic reagents. Doping natural phosphate with potassium fluoride significantly enhances the rate and yield of the reaction.

Nitrosocarbonyl intermediates, generated at r.t. by the mild oxidation of nitrile oxides, undergo clean ene reactions with tetramethyl- and trimethyl-ethylene and with cyclohexene. With less substituted ethylenes the ene pathway is still active but the oxidation step of the nitrile oxides competes with the cycloadditions to the olefins.

A novel and efficient metal-free carbon–nitrogen bond-forming coupling reaction between arylboronic acids and organic azides is reported. The reaction is fairly general for the preparation of secondary aromatic amines. Furthermore, the reaction is very functional-group tolerant. A possible mechanism is also proposed.

New synthons for carbocyclic nucleosides have been synthesized from 2-azabicyclo[2.2.1]hept-5-en-3-one readily available from cyclopentadiene, through introduction of an electron-withdrawing substituent at the 2-position followed by reduction with sodium borohydride.