Phosphorus containing mixed anhydridestheir preparation, labile behaviour and potential routes to their stabilisationElectronic supplementary information (ESI) available: Full crystallographic data. CCDC reference numbers 860547 (10), 860548 (11), 860549 (13). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2ob07164a

• Main Authors: Coetzee, Jacorien, Eastham, Graham R, Slawin, Alexandra M. Z, Cole-Hamilton, David J
• Format: Article
• Language: English
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/c2ob07164a

Simple mixed anhydrides are known to pose synthetic difficulties relating to their thermal lability and ways to stabilise such mixed anhydride systems by relying on either electronic or steric effects were therefore explored. Thus, a series of acyloxyphosphines and acylphosphites derived from either propanoic acid or phenylacetic acid were prepared and their in solution stability assessed. These compounds were, where stability allowed, fully characterised using standard analytical techniques. NMR studies, in particular, unearthed interesting coupling behaviour for a number of the acyloxyphosphines and acylphosphites as well as their rearrangement products which could be linked to their chiral nature. Furthermore, the crystal structures for three of the prepared mixed anhydrides were determined using X-ray crystallography and are reported herein. Reaction of propanoic acid with chlorophosphites produces mixed anhydrides, which are unstable towards disproportionation unless they bear substantial steric bulk in the 3 and 3 positions.