Synthesis of chiral vicinal diols and analysis of them by capillary zone electrophoresis.
This paper describes an improved access to 1,4-bis (9-O-quininyl) phthalazine [(QN)(2)PHAL], a very useful chiral ligand for catalytic asymmetric dihydroxylation (AD), by using CaH(2) as acid-binding reagent in a high yield under mild conditions. The application of (QN)(2)PHAL to the AD reactions of eight olefins exhibited excellent enantioselectivity and activity with corresponding chiral vicinal diols. Furthermore, a capillary zone electrophoresis method was developed to separate the aforementioned chiral vicinal diols by using of neutral beta-cyclodextrin (beta-CD) as chiral selector and borate as running buffer. High resolution was achieved under the optimal conditions of beta-CD 2.2% (w/v), pH 10, 200 mM borate buffer at 15 kV, and 20 degrees C within 15 min. The relative standard deviations of the corrected peak areas and migration time were less than 3.9% and 1.3%, respectively. In addition, the developed method was successfully applied to the determination of the purity and the enantiomeric excesses value (%ee) of the AD reaction products.
Research Center for Chirotechnology, Fourth Military Medical University, X'ian, Shaanxi, China.
Peng
P
Liu
Wei
W
He
Yan
Y
Zhao
Ping-An
PA
Wang
Xiao-Li
XL
Sun
Xiao-Ye
XY
Li
Sheng-Yong
SY
Zhang
D000475:Alkenes / Q000032:analysis* / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D001881:Borates / Q000737:chemistry; D002021:Buffers; D019075:Electrophoresis, Capillary; D006863:Hydrogen-Ion Concentration; D006900:Hydroxylation; D008024:Ligands; D010793:Phthalazines / Q000737:chemistry; D015203:Reproducibility of Results; D013237:Stereoisomerism; D013696:Temperature; D047392:beta-Cyclodextrins / Q000737:chemistry
D000475:Alkenes; D001881:Borates; D002021:Buffers; D008024:Ligands; D010793:Phthalazines; D047392:beta-Cyclodextrins; C031215:betadex