Non-standard experimental conditions can often enhance organocatalytic reactions considerably. The current study explores the effectiveness of a range of non-standard reaction conditions for the asymmetric organocatalytic 1,3-dipolar cycloaddition of a nitrone with α,β-unsaturated aldehydes. The influence of ionic liquids, high-pressure conditions, ultrasound, microwave irradiation and ballmilling was tested as well as the flow process. Because of the low reactivity of the nitrone and unsaturated aldehydes in the 1,3-dipolar cycloaddition, cycloadducts were isolated in only moderate yields from the majority of experiments. However, high diastereo- and enantioselectivities were observed in ionic liquids under solvent-free conditions and in the flow reactor.

Non-classical activation techniques improve the organocatalysed oxa-Diels–Alder reaction of aldehydes with enones.

Nitrones serve as starting materials for the synthesis of many heterocycles. Oxidation of secondary amines using hydrogen peroxide and the catalytic amount of methyltrioxorhenium in ionic liquids is a useful method for the preparation of nitrones. Ultrasonic irradiation and ionic liquids have a positive influence on the reaction. The nitrones required were isolated in good yields. Corresponding hydroxylamines, which can be easily oxidised to nitrones, often accompanied the main products. Methyltrioxorhenium in ionic liquids was re-used in several reaction cycles without any deteriorating effect on the course of the reaction.

Pyranones are formed under several conditions in the presence of pyrrolidine‐derived organocatalysts.