The acid-mediated ring opening/cyclisation reaction of N-benzyl-α-aryl-azetidinones
摘要:
N-Benzyl-4-aryl-azetidinones undergo ring opening with triflic acid to form N-benzyl-cinnamamides, which either undergo cyclisation to give 5-aryl-benzazepin-3-ones or N-debenzylation to give cinnamamides. (C) 2012 Elsevier Ltd. All rights reserved.
frontier in the development of chiral stationary phases for chromatographic enantioseparation involves homochiral metal–organic frameworks (MOFs). Using enantiopure (R)-2,2′-dihydroxy-1,1′-binaphthalene-6,6′-dicarboxylic acid as a starting material, we prepared three homochiral MOFs that were further used as chiral stationary phases for high-performanceliquidchromatography to separate the enantiomers
The acid-mediated ring opening reactions of α-aryl-lactams
作者:Frank D. King、Stephen Caddick
DOI:10.1039/c2ob00012a
日期:——
4-Aryl-azetidin-2-ones (β-lactams) undergo ring opening with triflic acid to give cinnamamides which, in benzene, react further to give 3-aryl-3-phenyl-propionamides. Prolonged reaction times in benzene give 3,3-diphenyl-propionamide via an aryl/phenyl exchange. Lactams of ring size 7 and higher also ring open, but only 7- and 8-membered rings give pure diphenylalkylamides. AlCl3 only ring opens the 4-aryl-azetidinones.
A New Route to Enantiopure β-Aryl-Substituted β-Amino Acids and 4-Aryl-Substituted β-Lactams through Lipase-Catalyzed Enantioselective Ring Cleavage of β-Lactams
作者:Enikő Forró、Tihamér Paál、Gábor Tasnádi、Ferenc Fülöp
DOI:10.1002/adsc.200505434
日期:2006.5
enantiomers through the CAL-B (lipase B from Candida antarctica)-catalyzed enantioselective (E>200) ringcleavage of the corresponding racemic β-lactams with 1 equiv. of H2O in i-Pr2O at 60 °C. The product (R)-β-amino acids (ee≥98%, yields≥42%) and unreacted (S)-β-lactams (ee≥95%, yields≥41%) could be easily separated. The ring opening of enantiomeric β-lactams with 18% HCl afforded the corresponding
Two novel chiral coordination polymers were synthesized by treating C2-symmetric 2,2′-dihydroxy- and 2,2′-dimethoxy-1,1′-binaphthalene-3,3′-dicarboxylic acids with Cu2+, in which sorption of some chiral β-lactam compounds in the frameworks occurred enantioselectively.