Me-BIPAM for the synthesis of optically active 3-aryl-3-hydroxy-2-oxindoles by ruthenium-catalyzed addition of arylboronic acids to isatins.
A chiral O-linked C(2)-symmetric bidentate phosphoramidite (Me-BIPAM) was found to be efficient for the ruthenium-catalyzed addition of arylboronic acids to isatins. Asymmetric synthesis of 3-aryl-3-hydroxy-2-oxindoles by 1,2-addition of arylboronic acids to isatins was carried out in the presence of [RuCl(2)(PPh(3))(3)]/(R,R)-Me-BIPAM and KF, resulting in an enantioselectivity as high as 90 % ee. It was found that the reaction with N-protected isatins proceeds with high yields and good enantioselectivities. The best protective groups on the nitrogen atom were different depending on the substituents on the aromatic ring. The use of a N-benzyl group resulted in excellent enantioselectivities in many substrates compared with other groups.
Frontier Chemistry Center, Faculty of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, 060-8628, Japan. yasuyama@eng.hokudai.ac.jp
Yasunori
Y
Yamamoto
Masaaki
M
Yohda
Tomohiko
T
Shirai
Hajime
H
Ito
Norio
N
Miyaura
D001897:Boronic Acids / Q000737:chemistry*; D002384:Catalysis; D007211:Indoles / Q000138:chemical synthesis / Q000737:chemistry*; D007510:Isatin / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*; D000078183:Oxindoles; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism
D001897:Boronic Acids; D007211:Indoles; D009943:Organophosphorus Compounds; D000078183:Oxindoles; C434331:phosphoramidite; C022960:2-oxindole; D012428:Ruthenium; D007510:Isatin