Preparation of the ylid (2) derived from 5(R)-phenylmorpholinone (1) in the presence of freshly prepared MgBr₂·Et₂O and dipolarophiles can lead to improved cycloaddition yields, with inverse diastereo- and regioselection compared to the corresponding uncatalysed reactions.

The Flack Parameter is now almost universally reported for all chiral materials characterized by X-ray crystallography. Its elegant simplicity was an inspired development by Howard Flack, and although the original algorithm for its computation has been strengthened by other workers, it remains an essential outcome for any crystallographic structure determination. As with any one-parameter metric, it needs to be interpreted in the context of its standard uncertainty.