Organophosphorus compounds with a phosphorus atom attached to a phenyl group and two organothio/organoseleno groups were synthesized using the rhodium-catalyzed insertion reaction of the PhP group of pentaphenylcyclopentaphosphine (PhP) with acyclic disulfides and diselenides. The method was applied to the synthesis of heterocyclic compounds containing the S-P-S group by the reaction of (PhP) and cyclic disulfides such as 1,2-dithietes, 1,2-dithiocane, 1,4,5-dithiopane, and 1,2-dithiolanes.

Rhodium-catalyzed isomerization and alkyne exchange reactions of 1,4-dithiines occurred by cleavage of two C−S bonds. The 2,5-and 2,6-disubstituted 1,4-dithiins underwent isomerization reactions in toluene at 110 °C, providing equilibrium mixtures of isomers. At 150 °C, the reaction of 1,4dithiins and dimethyl acetylenedicarboxylate gave unsymmetric 2 , 3 -d i ( m e t h o x y c a r b o n y l ) -1 , 4 -d i t h i i n s a n d 2 , 3 -d i -(methoxycarbonyl)thiophenes, the latter of which were formed by desulfurization of the 1,4-dithiins. A related reaction of the alkyne and a 1,2-dithiete gave a 2,3-di(methoxycarbonyl)thiophene. These reactions are considered to involve 1,2ethenedithiolato rhodium intermediates.