13C NMR Study of 3,9‐di(alkylphenoxy) ‐2,4,8,10‐tetraoxa‐3,9‐diphosphaspiro[5.5]undecanes

Abstract 13 C NMR chemical shifts and 13 C‐ 31 P coupling constants of fourteen derivatives from 3,9‐di(alkylphenoxy)‐2,4,8,10‐tetraoxa‐3,9‐diphosphaspiro[5.5]undecane and of eight derivatives of the 3,9‐dioxo type are reported. All investigated compounds possess a chair conformation with the lone pair or the phosphoryl oxygen in the equatorial position. The alkylphenoxy groups are in a cis position with respect to the lone pair or the phosphoryl oxygen. Conformational changes about the arylO bond can be monitored via 31 POC 13 C couplings and their angular dependence was found to be non‐symmetric.