Synthesis of 4-Unsubstituted β-Lactams<i>via</i>Dithiocarbonimidates
作者:S. D. Sharma、Usha Mehra、J. P. S. Khurana、S. B. Pandhi
DOI:10.1055/s-1987-28144
日期:——
Cycloaddition of dithiocarbonimidate 1 to the ketene generated in situ from phenoxyacetylchloride in the presence of triethylamine affords the 4-dithioalkyl-2-azetidinones 2 in good yields. Facile conversion of 2 to the 4-unsubstituted ß-lactams 3 can be accomplished by desulfurization with Raney-Nickel. Formation of several interesting products during attempts to bring a carbonyl function at C-4 in 2 has also been described.
作者:Benito Alcaide、Alberto Rodríguez-Vicente、Miguel A. Sierra
DOI:10.1016/s0040-4039(97)10476-2
日期:1998.1
C4-Unsubstituted beta-lactams 3 are conveniently prepared from easily available 4-formyl-beta-lactams 1, in a sequential three step synthesis, using as the key step a radical reductive decarbonylation of 4-carboxy derivatives through their phenyl selenoesters 2. (C) 1997 Elsevier Science Ltd. All rights reserved.
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.