(1R,2S,4r)-1,2,4-Tri-phenyl-cyclo-pentane-1,2-diol and (1R,2S,4r)-4-(2-meth-oxy-phen-yl)-1,2-di-phenyl-cyclo-pentane-1,2-diol: application as initiators for ring-opening polymerization of ∊-caprolactone.

Reductive cyclization of 1,3,5-triphenyl- and 3-(2-meth-oxy-phen-yl)-1,5-di-phenyl-pentane-1,5-diones by zinc in acetic acid medium leads to the formation of 1,2,4-tri-phenyl-cyclo-pentane-1,2-diol [1,2,4-Ph(3)C(5)H(5)-1,2-(OH)(2), C(23)H(22)O(2), (I)] and 4-(2-meth-oxy-phen-yl)-1,2-di-phenyl-cyclo-pentane-1,2-diol [4-(2-MeOC(6)H(4))-1,2-Ph(2)C(5)H(5)-1,2-(OH)(2), C(24)H(24)O(3), (II)]. Their single crystals have been obtained by crystallization from a THF/hexane solvent mixture. Diols (I) and (II) crystallize in ortho-rhom-bic (Pbca) and triclinic (P ) space groups, respectively, at 150†K. Their asymmetric units comprise one [in the case of (I)] and three [in the case of (II)] crystallographically independent mol-ecules of the achiral (1R,2S,4r)-diol isomer. Each hydroxyl group is involved in one intra-molecular and one inter-molecular O-H⋯O hydrogen bond, forming one-dimensional chains. Compounds (I) and (II) have been used successfully as precatalyst activators for the ring-opening polymerization of ∊-caprolactone.