Premium
Stereocontrol of the Schiff Base of Substituted Benzaldehyde to Staudinger Cycloaddition Reaction
Author(s) -
ChuanMin Qi,
LingChun Yang,
PengLi Sun
Publication year - 2003
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.20030210618
Subject(s) - chemistry , benzaldehyde , schiff base , cycloaddition , yield (engineering) , benzene , medicinal chemistry , ring (chemistry) , stereoselectivity , base (topology) , stereochemistry , organic chemistry , catalysis , materials science , metallurgy , mathematical analysis , mathematics
Syntheses of 4 novel chiral azetidin‐2‐one derivatives, which were characterized by 1 H NMR, ER, specific rotation and elemental analysis, through Staudinger cycloaddition reaction of Schiff base of benzaldehyde with chlorine substitution at different position in benzene ring, were described. For the first time, this type of 3 S , 4 R configuration azetidin‐2‐one mono‐crystals with many chiral centers [(3 S ,4 R )‐3‐hydroxy‐ N ‐[(S)‐(1‐phenyl)ethyl]‐4‐(2′‐chlorophenyl)‐azetidin‐2‐one mono‐crystal] were obtained, the structures of which were determined by X‐ray diffraction analysis. The effects of Schiff base of benzaldehyde with chlorine substitution at different position in benzene ring on stereoselectivity of Staudinger cycloaddition reaction products were discussed and the results are showed as below: 2‐chlorophenyl Schiff base favored to yield 3 S. 4 R configuration product, but 4‐chlorophenyl Schiff base favored to yield 3 S ,4 S configuration product. The reaction orientation of 2,4‐dichlorophenyl Schiff base was determined by corporate effect of 2‐and 4‐chlorine, and that of the 4‐chlorine was more obvious. In contrast to 4‐chlorophenyl, although the main product was 3 R , 4 S configuration, 3‐chlorophenyl owned lower selectivity.