Developing selective access to P(<scp>v</scp>)/(<scp>v</scp>) and a heteroatom-bridged P(<scp>iii</scp>)P(<scp>v</scp>) 1,4-diphosphabarrelene(s) using a 1,4-diphosphinine

1,4-Diphosphabarrelene dioxides and disulfides have been directly synthesized from C-functional 1,4-diphosphabarrelenes. Additionally, a tricyclic 1,4-diphosphinine enabled access to both a P(V)/(V) derivative using cyclohexene sulfide and the first heteroatom-bridged P(III)/(V) 1,4-diphosphabarrelene <i>via</i> an oxidative cycloaddition with 5,5-dimethylpyrroline <i>N</i>-oxide.