The oximeethers (7) and (8)(R = alkyl or aryl) undergo base-catalysed elimination to benzonitriles (3) in water–dioxan (4 : 1) at 25°. The Z-isomer (8Z) reacts via hydroxide-catalysed antiperiplanar elimination 70-fold more rapidly than the corresponding E-isomer. Electronic effects on syn-elimination (from 7E) show that electronwithdrawing groups aid elimination in both Ar and in the leaving group
Enantioselective bioreduction of ( E )-1-phenyl-1,2-alkanedione 2-( O- methyloxime)
作者:Olyr C Kreutz、Renata C.M Segura、J.Augusto R Rodrigues、Paulo J.S Moran
DOI:10.1016/s0957-4166(00)00163-4
日期:2000.6
The baker's yeast reduction of (E)-1-phenyI-1,2-alkanedione 2-(O-methyloxime), PhC(O)C(NOMe)R (R = Me, Et, n-Pr, n-Bu), gave the corresponding optically active alcohols PhCH2OHC(NOMe)R in 88-99% enantiomeric excess and 48-75% chemical yield. The R configuration was proposed for these alcohols based on circular dichroism analysis. Only the phenylglyoxal O-methylaldoxime (R=H) gave poor enantiomeric excess (65%) and chemical yield (14%). These compounds are potential chiral building blocks for the stereoselective synthesis of norephedrine analogs. (C) 2000 Elsevier Science Ltd. All rights reserved.
Reactions of ?-oximinoketones with diazomethane
作者:A. V. Prosyanik、Ya. Z. Zorin、A. I. Mishchenko、V. M. Negrimovskii、A. B. Zolotoi
DOI:10.1007/bf00948518
日期:1985.8
HEGARTY A. F.; TUOHEY P. J., J. CHEM. SOC. PERKIN TRANS., 1980, PART 2, NO 9, 1313-1317
作者:HEGARTY A. F.、 TUOHEY P. J.
DOI:——
日期:——
PROSYANIK, A. V.;ZORIN, YA. Z.;MISHCHENKO, A. I.;NEGRIMOVSKIJ, V. M.;ZOLO+, IZV. AN CCCP. CEP. XIM., 1985, N 8, 1840-1847
作者:PROSYANIK, A. V.、ZORIN, YA. Z.、MISHCHENKO, A. I.、NEGRIMOVSKIJ, V. M.、ZOLO+