Improving catalyst activity in secondary amine catalysed transformations.

The effect on catalyst performance of altering substituents at the 2-position of the Macmillan imidazolidinone has been examined. Condensation of L-phenylalanine N-methyl amide with acetophenone derivatives results in a series of imidazolidinones whose salts can be used to accelerate the Diels-Alder cycloaddition. Electron withdrawing groups significantly increase the overall rate of cycloaddition without compromise in selectivity.

Readily accessible chiral at nitrogen cage structures.

The reaction of glycine-N-methyl amide with paraformaldehyde in the presence of ytterbium triflate (1 mol%) leads to a novel cage structure 6 which is chiral at nitrogen. Single crystal X-ray analysis and DFT calculations suggest this cage structure is rigid and adopts a single low energy conformation. Use of single enantiomer α-amino amides results in two diastereomeric tertiary amines that differ in their absolute configuration at nitrogen.

Synthesis of the pyoverdin chromophore by a biomimetic oxidative cyclization.

The fluorescent dihydropyrimido[1,2-a]quinoline chromophore of the pyoverdin siderophores has been synthesized by a biomimetic oxidative cyclization using an iodine(III) reagent, followed by elimination and dehydrogenation.

Direct alpha-oxytosylation of carbonyl compounds: one-pot synthesis of heterocycles.

N-Methyl-O-tosylhydroxylamine is an effective reagent for the direct alpha-oxytosylation of carbonyl compounds. The reactions proceed smoothly at room temperature in the presence of both moisture and air and functional group tolerance in the substrate is good. With nonsymmetrical substrates regioselectivity for primary over secondary centers is observed and complete regiospecificity for primary over tertiary centers is obtained.