Stereoselectivity with a twist

As strategies for making stereodefined structures go, taking readily available chiral building blocks and building them into new molecules is essentially ideal. Unfortunately, asymmetric catalysis has not been able to take advantage of natural sources of handedness in the same way. 

Michinori Suginome and his team at Kyoto University, Japan, have come up with a fascinating strategy using limonene – a readily available, colourless, chiral hydrocarbon extracted from peel of citrus fruits – to control the stereochemical outcome of catalytic reactions. But rather than using it as a ligand, it is used as the solvent. The chirality is then transferred through a helical macromolecular ‘helper’ to provide stereoselectivity in palladium-catalysed reactions.