Phosphorus-based ligands continue to play a pivotal role in the development of stereoselective transition-metal-catalyzed reactions. Although phosphine-based ligands have been extensively used in the optimization of catalytic processes, the use of readily modifiable phosphite or phosphonite ligands offers an attractive alternative to phosphine-based ligands. Recently, sterically hindered bis(phosphite) ligands incorporating the seven-membered dibenzo[d,f][1,3,2]dioxaphosphepin ring system were reported to be an effective ligand for rhodium-catalyzed hydroformylation reactions (Figure 1).(2) Van Leeuwen et al. suggested that the large natural bite angle in ligands such as I increases the stereoselectivity of the rhodium (I)-catalyzed hydroformylation reaction.(3) A relationship between the ratio of normal to iso olefin hydroformylation as a function of ligand bite angle has been established.(4) Gladfelter et al. made the important observation that the geometric inclination of the bis (phosphite) ruthenium carbonyl complex (P-Ru-P bond angle of 118.98degrees) prepared from 2 is due to steric rather than electronic factors.(5) Nevertheless, the ratio of iso to normal olefin hydroformylation has been shown in an elegant study by Casey to be subject to electronic effects.(6) In principle, the facile preparation of aryl phosphites or phosphonites with electron-accepting or -donating groups allows for the tailoring of sterically congested bis(phosphonite) ligands based upon the ferrocene motif.