Reagents and synthetic methods. Part 67. Preparation of 4-unsubstituted .beta.-lactams from 4-acetoxyazetidin-2-ones. A formal approach to monobactams and nocardicins
The enolates derived from 2-pyridylthioesters by reaction with BCl3 ·SMe2 and enantiomerically pure aminoalcohols react with aromatic imines in an enantioselective fashion (ee up to 78%) to afford β-lactams in a convenient one-pot procedure.
A short formal synthesis of the carbapenem antibiotic (±)-PS-5
作者:José M. Odriozola、Fernando P. Cossío、Claudio Palomo
DOI:10.1039/c39880000809
日期:——
A practical stereoselective synthesis of 4-acetoxy-3-ethylazetidin-2-one via Reformatsky reaction between methyl-α-bromobutyrate and N-4-methoxyphenyl-α-methylcinnamyildeneamine is described.
Preparation of 3-alkyl .beta.-lactams via the ketene imine cycloaddition reaction using .alpha.-(phenylthio)alkanoyl halides as starting materials: application to the synthesis of (.+-.)-carbapenem building blocks and related compounds
作者:Claudio Palomo、Fernando P. Cossio、Jose M. Odiozola、Mikel Oiarbide、Jesus M. Ontoria
DOI:10.1021/jo00014a017
日期:1991.7
Preparation of appropriately substituted 3-alkyl beta-lactams via the ketene (or equivalent)-imine cycloaddition reaction is described. The dehydrochlorination reaction of alpha-(phenylthio)alkanoyl chlorides with triethylamine in the presence of imines derived from cinnamaldehydes and p-anisidine produced a high-yield formation of alpha-phenylthio beta-lactams, which upon desulfuration furnished a variety of 3-alkyl beta-lactams in a highly stereoselective fashion. In contrast, reaction between alpha-haloalkanoyl chlorides and cinnamylideneamines in the presence of triethylamine furnished the corresponding [4 + 2] cycloadducts as main products. Preparation of highly functionalized alpha-alkylidene beta-lactams through thermal decomposition of the corresponding beta-lactam sulfoxides or by cycloaddition of alpha,beta-unsaturated acid chlorides to imino esters in the presence of triethylamine is also described. Addition of Flemming's silylcuprate reagent to alpha-alkylidene beta-lactams furnished the corresponding 3-(1'-(dimethylphenylsilyl(ethyl) beta-lactams as (+/-)-thienamycin intermediates.
Alkyl(phenylthio)ketenes as synthetic equivalents of monoalkylketenes: A concise general route to 3-alkyl β-lactams as carbapenem building-blocks
作者:Claudio Palomo、Fernando P. Cossío、José M. Odriozola、Mikel Oiarbide、Jesús M. Ontoria
DOI:10.1016/s0040-4039(01)80749-8
日期:1989.1
A concise synthesis of 4-unsubstituted azetidin-2-ones
作者:Fernando P. Cossío、Begoña Lecea、Claudio Palomo
DOI:10.1039/c39870001743
日期:——
On catalysis by trimethylsilyl trifluoromethanesulphonate, 4-acetoxy-β-lactams react with hydrosilanes to give 4-unsubstituted-β-lactams in good to excellent yields.