New bulky chiral Lewis acid catalyst: 3,3'-di(2-mesitylethynyl)binaphthol-titanium(IV) complex.
A new chiral Lewis acid catalyst 9 was prepared in situ from a 1:2 molar mixture of (R)-3,3'-di(2-mesitylethynyl)binaphthol (6) and titanium(IV) isopropoxide at ambient temperature. The 3- and 3'-substituents on 6 were effective for preventing undesired aggregation between Ti(IV) complexes and increasing the enantioselectivity (up to 82% ee) in the Diels-Alder reaction of methacrolein with cyclopentadiene.
Ishihara
Kazuaki
K
Graduate School of Engineering, Nagoya University, SORST, Japan Science and Technology Corporation (JST), Furo-cho, Chikusa 464-8603, Nagoya, Japan.
Kobayashi
Jun
J
Nakano
Kazuhiko
K
Ishibashi
Hideaki
H
Yamamoto
Hisashi
H