Synthesis of New Chiral Ligands and Their Group VI Metal Alkylidene Complexes

The new chelating chiral diol ligands (1S,2S)- and (1R,2R)-1,2-bis(2-hydroxy-2,2-bis(trifluoromethyl)ethyl)cyclopentane (TBEC-H_2; 1) were synthesized. The dilithium alkoxide of TBEC was reacted with Mo(CHCMe_2Ph)(NAr)(OTf)_2dme (2; Ar = 2,6-(i-Pr)_2C_6H_3) to give the chiral alkylidene complex Mo(CHCMe_2Ph)(NAr)(TBEC) (3). The ligand also reacts with W(η^2-diphenylcyclopropene)Cl_2(O)[P(OMe)_3]_2 (4), W(CHCHCOCH2CH2CH2O)(O)Cl_2[P(OMe)_3] (5), and W(CHCHCPh_2)(NAr)Cl_2[P(OMe)_3]_2 (6; Ar = 2,6-(i-Pr)_2C_6H_3) to the give stable corresponding tungsten oxo vinylalkylidene complexes and tungsten amide vinylalkylidene complexes, respectively. These group VI alkylidene complexes show excellent catalytic activity in both ring-opening metathesis polymerization and in ring-closing metathesis processes.