PHOSPHORANYLATIONS - PREPARATION OF 5-MEMBERED CYCLIC OXYPHOSPHORANES AND SPIROOXYPHOSPHORANES FROM REACTION OF PENTAPHENOXYPHOSPHORANE WITH CATECHOL

One mole of catechol displaced two moles of phenol from pentaphenoxyphosphorane (δ31P = + 85·6 ppm vs H3PO4) in CH2Cl2 and gave catecholtriphenoxyphosphorane (δ31 P = +60·8 ppm). Two moles of catechol displaced four moles of phenol from pentaphenoxyphosphorane and gave spirodicatecholphenoxyphosphorane (δ31P = +29·8 ppm). The 5-membered cyclic pentaoxyphosphoranes are more stable than the acyclic analogues because the intramolecular crowding present in the trigonal bipyramidal structure of pentavalent phosphorus is minimized when the groups on the phosphorus are held in a ring. The reaction of catechol with PCl5 was investigated in various solvents at several temperatures, using various mole ratios of the reactants. Previously suggested structures for trichlorocatecholphosphorane (δ31P = +26·5 ppm) and for chlorospirodicatecholphosphorane (δ31P = +9·4 ppm) were confirmed. However, the structure of a catechol-bis(spirodicatecholphosphorane) now in the literature, was shown to be in error. The procedures now in the literature for the synthesis of catecholtriphenoxyphosphorane and of spirodicatecholphenoxyphosphorane did not lead, in fact, to these substances. © 1968.