Chiral Pyridinium Phosphoramide as a Dual Brønsted Acid Catalyst for Enantioselective Diels-Alder Reaction.
Chiral pyridinium phosphoramide 1·HX was designed to be a new class of chiral Brønsted acid catalyst in which both the pyridinium proton and the adjacent imide-like proton activated by the electron-withdrawing pyridinium moiety could work cooperatively as strong dual proton donors. The potential of 1·HX was shown in the enantioselective Diels-Alder reactions of 1-amino dienes with various dienophiles including N-unsubstituted maleimide, which has yet to be successfully used in an asymmetric Diels-Alder reaction.
Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan.
Yasuhiro
Y
Nishikawa
Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan.
Saki
S
Nakano
Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan.
Yuu
Y
Tahira
Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan.
Kanako
K
Terazawa
Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan.
Ken
K
Yamazaki
Department of Materials Science, School of Engineering, The University of Shiga Prefecture , 2500 Hassaka-cho, Hikone, Shiga 522-8533, Japan.
Chitoshi
C
Kitamura
Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya, Aichi 468-8503, Japan.
Osamu
O
Hara