Kinetically controlled optical resolution of racemic norbornene aldehyde derivatives.
A new method for obtaining optically pure 5-norbornene 2-endo-aldehyde derivatives was developed. The reaction of a diastereomeric mixture of the ene acetals 2 and 2', derived from racemic norbornene aldehydes (+/-)-1 and chiral nonracemic (S,S)-hydrobenzoin 7, with NBS (0.5-0.6 eq.) in the presence of H(2)O proceeded in a kinetically controlled manner to give the optically pure hydroxy aldehydes 3 along with the intact ene acetals 2'. Both compounds 3 and 2' were converted into the optically pure norbornene aldehydes 1 and ent-1, respectively. This method opens the way to produce various types of 5-norbornene 2-endo-aldehydes with 3-exo- or 3-endo-substituents in optically pure forms.
Fujioka
Hiromichi
H
Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan. fujioka@phs.osaka-u.ac.jp
Kotoku
Naoyuki
N
Fujita
Tetsuya
T
Inoguchi
Ryoko
R
Murai
Kenichi
K
Nagatomi
Yasushi
Y
Sawama
Yoshinari
Y
Kita
Yasuyuki
Y
D000447:Aldehydes / Q000737:chemistry*; D007202:Indicators and Reagents; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D009636:Norbornanes / Q000737:chemistry*; D013237:Stereoisomerism
D000447:Aldehydes; D007202:Indicators and Reagents; D009636:Norbornanes