Synthesis of versatile chiral intermediates by enantioselective conjugate addition of alkenyl Grignard reagents to enamides deriving from (R)-(−)- or (S)-(+)-2-aminobutan-1-ol
作者:Eric Brown、Christelle Deroye、Joël Touet
DOI:10.1016/s0957-4166(98)00135-9
日期:1998.5
Conjugate addition of but-3-enylmagnesium bromide to the chiral crotonamide (R)-(+)- and (S)-(−)-3, followed by hydrolysis and oxidation, afforded enantiopure (R)-(+)- and (S)-(−)-3-methyladipic acids 8, respectively. Conjugate addition of vinylmagnesium chloride to the chiral crotonamide and cinnamamides (R)-(+)-3–5, followed by hydrolysis, gave the alkenoic acids (S)-12–14, respectively. Iodolactonization
Enantioselective Michael additions of Grignard reagents to cinnamamides deriving from N-fluoroalkyl (R)-(−)-2-aminobutan-1-ol. determination of diastereomeric excess by means of 19F NMR
作者:Joël Touet、Christelle Le Grumelec、François Huet、Eric Brown
DOI:10.1016/s0957-4166(00)80345-6
日期:1993.7
N-Alkylation of (R)-(-)-2-aminobutan-1-ol 1 (a readily available reagent) with ortho-fluorobenzyl chloride, followed by reaction with cinnamoyl chloride, afforded the cinnamamide (R)-(+)-6. Michael addition of n-alkyl magnesium halides to the latter gave the corresponding adducts (R,R)-8a-e whose diastereomeric excesses were higher than 92% as evidenced by F-19 NMR. Acidic hydrolysis of these adducts yielded the corresponding beta-phenylalkanoic acids (R)-(-)-9a-e.
Brown, Eric; Deroye, Christelle; Huet, Francois, Journal of Chemical Research, Miniprint, 1997, # 10, p. 2227 - 2243
作者:Brown, Eric、Deroye, Christelle、Huet, Francois、Grumelec, Christelle Le、Touet, Joel