Selectivity in reactions of tricyclic phosphatranes. Pseudo-equatorial nucleophilic attack on the trigonal bipyramidal configuration of phosphorus. X-Ray crystal structure of [EtSP(OCH2CH2)3N]+BF4–

Abstract

Reactions of tricyclic phosphatranes [RXP(OCH₂CH₂)₃N]⁺BF₄^–; X = O, S and R = Me, Et, in which a transannular N → P bond brings phosphorus in a trigonal bipyramidal configuration, with nucleophiles (e.g. OH^–) result exclusively in a nucleophilic attack on a pseudo-equatorial carbon atom, irrespective of the nature of the carbon atom in the apical ligand (XR).