New .beta.-lactam acetic acid derivatives I ##STR1## wherein R represents alkyl, alkyl substituted with amino, protected amino, mono- or di-alkylamino, hydroxy, protected hydroxy or alkoxy, and alkenyl, and their salts are useful as intermediates for preparing 1-azabicyclo [3.2.0]hept-2-ene antibiotics II ##STR2## The process for preparing the .beta.-lactam acetic acid derivatives I as well as the overall process which starting from the acids I leads to the antibiotics II are also claimed.
A highly diastereoselective aldol reaction of dicobalt hexacarbonyl propynal complex and uncomplexed propynal: A stereoselective divergent synthesis of (±)-PS-5 and (±)-6-Epi-PS-5
作者:Chisato Mukai、Osamu Kataoka、Miyoji Hanaoka
DOI:10.1016/0040-4039(91)80532-b
日期:1991.12
The aldol reaction of cobalt complexes propynal 1 with O-silyl keteneO,S-acetals 3 gave the syn-products exclusively, while the uncomplexed propynal 2, the corresponding anti-compounds. A successful application of these stereoselective reactions to a synthesis of (±)-PS-5 and (±)-6-epi-PS-5 is described.
A photochemical route to carbapenems from pyrazolidin-3-ones. Formal synthesis of PS-5
作者:James D. White、Steven G. Toske
DOI:10.1016/s0040-4039(00)60548-8
日期:1993.1
Photochemical ring contraction of a cis disubstituted pyrazolidin-3-one, prepared by hydrazinolysis of an α, β-unsaturated δ-lactone, gave the corresponding azetidinone which has been converted previously to the carbapenem antibiotic PS-5.