Electroreduction of 3-bromo- and 3, 3-dichloro-β-lactams 1 carried out at the potential of the first voltammetric peak and in the presence of acetic anhydride gives 3-acetyl-β-lactams 2. The electrosynthesis is highly stereoselective, as only the acetyl derivative with trans configuration is formed.
Stereoselective synthesis of trans- and cis-2-aryl-3-(hydroxymethyl)aziridines through transformation of 4-aryl-3-chloro-β-lactams and study of their ring opening
作者:Matthias D'hooghe、Karen Mollet、Stijn Dekeukeleire、Norbert De Kimpe
DOI:10.1039/b919864d
日期:——
cis-2-aryl-3-(hydroxymethyl)aziridines via reductive ring contraction using LiAlH4 in Et2O. Furthermore, trans-2-aryl-3-(hydroxymethyl)aziridines were transformed into 2-amino-3-arylpropan-1-ols and anti-2-amino-3-aryl-3-methoxypropan-1-ols by means of an unprecedented ring opening by LiAlH4 and by MeOH, respectively. cis-2-Aryl-3-(hydroxymethyl)aziridines were shown to be highly reluctant to undergo ring opening by
Multifaceted interception of 2-chloro-2-oxoacetic anhydrides: a catalytic asymmetric synthesis of β-lactams
作者:Li Huang、Wenjun Zhao、Richard J. Staples、William D. Wulff
DOI:10.1039/c2sc21240d
日期:——
N-carboxyanhydrides or β-lactams depending on the nature of the substituent at the 3-position. All substrates can be diverted to β-lactams upon treatment with a Vilsmeier reagent. The three to four membered ring expansion is stereospecific and proceeds with high yields and diastereoselection. This method provides for an asymmetricsynthesis of β-lactams from simple aldehydes via a multi-component catalytic asymmetric
The Halogen-Lithium Exchange Reaction of 3,3-Dichloro-2-azetidinones: Application to the Synthesis of<b>
<i>cis</i>
</b>-4-Aryl-3-chloro-2-azetidinones
作者:Norbert De Kimpe、Yves Dejaegher、Bram Denolf、Christian V. Stevens
DOI:10.1055/s-2004-831248
日期:——
A straightforward synthesis of new cis-4-aryl-3-chloro-2-azetidinones was developed, using a halogen-lithium exchangereaction on 4-aryl-3,3-dichloro-2-azetidinones. This methodology was further extended to the use of alkyl halides as electrophiles, while more complex electrophiles could not be introduced.