title: Rhodium-catalyzed asymmetric 1,4-addition of aryltitanium reagents generating chiral titanium enolates: isolation as silyl enol ethers.
abstract: The addition of aryltitanium triisopropoxide (ArTi(OPr-i )3) to alpha,beta-unsaturated ketones proceeded with high enantioselectivity (94-99.8% ee) in the presence of 3 mol % of [Rh(OH)((S )-binap)]2 in THF at 20 degrees C to give high yields of the titanium enolates as 1,4-addition products. The titanium enolates were converted into silyl enol ethers by treatment with chlorotrimethylsilane and lithium isopropoxide.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan. thayashi@kuhem.kyoto-u.ac.jp
authors.forename: Tamio
authors.initials: T
authors.lastname: Hayashi
authors.forename: Norihito
authors.initials: N
authors.lastname: Tokunaga
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yoshida
authors.forename: Jin Wook
authors.initials: JW
authors.lastname: Han