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

The new chelating chiral diol ligands (1 S,2 S )- and (1 R,2 R )-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 2 Ph)(NAr)(OTf) 2 dme ( 2; Ar = 2,6-( i -Pr) 2 C 6 H 3 ) to give the chiral alkylidene complex Mo(CHCMe 2 Ph)(NAr)(TBEC) ( 3 ). The ligand also reacts with W(η 2 -diphenylcyclopropene)Cl 2 (O)[P(OMe) 3 ] 2 ( 4 ), W(CHCHCOCH 2 CH 2 CH 2 O)(O)Cl 2 [P(OMe) 3 ] ( 5 ), and W(CHCHCPh 2 )(NAr)Cl 2 [P(OMe) 3 ] 2 ( 6; Ar = 2,6-( i -Pr) 2 C 6 H 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.