1-phosphabicyclo[3.2.1]octanes

1-Phosphabicyclo[3.2.1]octane has been obtained by free-radical cyclization of (2-vinyl-4-pentenyl)-phosphane in the presence of AIBN. Another approac h to 1-phosphabicyclo[3.2.1]octanes involves free-radical cyclization of 2- methyl-4-(2-propenyl)-phospholane synthesized by the reaction of [2-(2-prop eny)-4-pentenyl]-phosphane with KPH2/crowding of the phosphanes as complex ligands has been estimated from P-31-H-1 coupling constants according to th e Tolman model. The configuration of the methyl substituents as well as the conformation of the six-membered ring were determined by NMR parameters (c oupling constants, noe's) and proved by X-ray crystal structure analysis.