Stereodivergent synthesis of chiral 2-alkenylaziridines: palladium(0)-catalyzed 2,3-cis-selective aziridination and base-mediated 2,3-trans-selective aziridination.
Whereas treatment of the allylic mesylates of N-protected 2-alkyl-4-amino-(E)-2-alken-1-ols with sodium hydride in DMF yields exclusively the corresponding thermodynamically less stable 2,3-trans-2-alkenyl-3-alkylaziridines, exposure of the methyl carbonates of N-protected 2-alkyl-4-amino-(E)-2-alken-1-ols to a catalytic amount of Pd(PPh(3))(4) in THF or 1,4-dioxane affords predominantly the corresponding thermodynamically more stable 2,3-cis-2-alkenyl-3-alkylaziridines. The kinetically favored trans-selective aziridination would be attributed to the allylic 1,3-strain in aza-anionic intermediates. The conformational analysis of the sterically highly congested 2-alkenylaziridines thus obtained is also presented.
Ohno
Hiroaki
H
Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan.
Takemoto
Yoshiji
Y
Fujii
Nobutaka
N
Tanaka
Tetsuaki
T
Ibuka
Toshiro
T
D001388:Aziridines / Q000138:chemical synthesis* / Q000494:pharmacology*; D002384:Catalysis; D018360:Crystallography, X-Ray; D003500:Cyclization; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D010165:Palladium / Q000737:chemistry*; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013237:Stereoisomerism; D013816:Thermodynamics
D001388:Aziridines; D007202:Indicators and Reagents; D010165:Palladium