| 15255729 |
Dong C, Alper H: Catalytic asymmetric cyclocarbonylation of o-isopropenylphenols: enantioselective synthesis of six-membered ring lactones. J Org Chem. 2004 Jul 23;69(15):5011-4.
Cyclocarbonylation of o-isopropenylphenols with CO (500 psi) and H (2) (100 psi), using Pd (OAc)(2) and (+)-DIOP as the chiral catalyst, in CH (2) Cl (2) affords 3,4-dihydro-4-methylcoumarins in 60-85% yield and in up to 90% enantiomeric excess. The stereoselectivity is influenced by the structure of the chiral phosphine ligands and substrates, as well as by the reaction conditions. |
1(0,0,0,1) |