Preparation and properties of sterically protected diphosphene and fluorenylidenephosphine bearing the 2,6-di-tert-butyl-4-methoxyphenyl group

A new bulky bromobenzene, 2-bromo-1,3-di-tert-butyl-5-methoxybenzene, was prepared and utilized to preparations of the corresponding diphosphene and fluorenylidenephosphine including low-coordinate phosphorus atom(s). An electronic perturbation of the p-methoxy group in the system was indicated by UV-vis spectra and P-31 NMR chemical shifts.