Formation of new organoselenium heterocycles and ring reduction of 10-membered heterocycles into seven-membered heterocycles

Seven- and 10-membered phosphorus-selenium heterocycles can be readily prepared by the selenation of aromatic diol (2,2′-diphenol or 1,1′-bi(2-naphthol)) and 10-membered rings can be reduced into the corresponding seven-membered monophosphorus species by loss of one molecule of H2Se and one molecule of Se via reaction with another molar of aromatic diol.