Five-membered rings with two nonadjacent heteroatoms with at least one phosphorus, arsenic, or antimony

Developments in the chemistry of five-membered ring heterocycles containing two non-adjacent heteroatoms, with at least one phosphorus, in the period 2008–2020 are reviewed. Application of theoretical and structural methods to these compounds is described including X-ray structure determination and 31P NMR. The major reactions of azaphosphole and oxaphosphole systems and particularly their benzo analogues are discussed. There have been major developments in the chemistry of benzazaphospholes, benzoxaphospholines and to a lesser extent benzothiaphospholes. Methods for the synthesis of all the compounds are systematically covered. The systematic development of chiral benzoxaphospholines as some of the most valuable ligands for asymmetric transition metal catalysis has provided much of the impetus for developments in this area and this application is summarised in detail with the most recent examples.