A concise formal approach to the oxacephem skeleton from an intramolecular Peterson type olefination of N-[bis(trimethylsilyl)methyl]-β-lactams.
作者:Claudio Palomo、Jesu´s M. Aizpurua、Jesu´s M. Garcta、Jean Paul Picard、Jacques Dunogue´s
DOI:10.1016/s0040-4039(00)98818-x
日期:1990.1
A convenient synthesis of precursors of bicyclic β-lactam compounds from 4-acetoxy-1-(bistrimethylsilylmethyl)azetidin-2-ones prepared in few steps from the acid chloride-imine approach is described. A novel method to construct a bicyclic β-lactam ring system through an intramolecular Peterson type alkenation catalyzed by fluoride ion is also made.
Swapping N,P for C,N: Iridium complexes of bidentate pyridine‐based C,Nligands with an N‐heterocylic carbene (NHC) unit proved to be efficient and highly enantioselective hydrogenation catalysts. As a result of the lower acidity of iridium hydride intermediates produced from NHC‐based complexes, these catalysts are much better suited than analogous N,P‐ligand complexes for the hydrogenation of acid‐sensitive