Abstract: | 1‐Phosphabicyclo2.2.1]heptanes Exo‐endo‐ and exo‐exo‐2.6‐dimethyl‐1‐phosphabicyclo 2.2.1]heptane have been obtained by cyclization of 2‐methyl‐4‐(2‐propenyl)phospholane in the presence of the complex base, sodium salt of diethylenglycolmonoethylether ‐ sodium amide in THF (NAMEDEG). The bicyclic phosphanes are characterized by reac‐tions with selenium, sulfur, (CH3)2SeO, CH3I and HSO3F, respectively, elemental analysis, X‐ray crystal structure analysis as well as 1H, 13C, 31P NMR spectral measurements. The steric demand of these phosphanes as complex ligands has been estimated from the P, H coupling constants of the phosphonium fluorosulphates according to the Tolman model. The phosphane selenides were found to display the lowest values for the 1J(Se, P) coupling constant, found up to now for alicyclic and cyclic aliphatic tertiary phosphane selenides. The nJ(P, H)‐ and nJ(H, H)n=2, 3 coupling constants have been extracted from the proton spectra at 600 MHz by computerized analysis. |