B. Alcaide et al., SYNTHESIS OF FUSED TRICYCLIC BETA-LACTAMS BY THE PAUSON-KHAND CYCLIZATION OF ENYNE-2-AZETIDINONES, Tetrahedron letters, 37(38), 1996, pp. 6901-6904
Reaction of enyne-beta-lactams 1 with Co-2(CO)(8) followed by in situ
thermal or TMANO decomposition of the formed alkyne-Co-2(CO)(6) comple
xes gives tricyclic beta-lactams 2 as single stereoisomers, in good to
excellent yields. These are the first examples of an intramolecular P
auson-Khand reaction on an enyne system tethered to a four membered ri
ng. Copyright (C) 1996 Elsevier Science Ltd