Sequential Diimination, Staudinger [2 + 2] Ketene-Imine Cycloaddition, and Ring-Closing Metathesis (RCM) Reactions: In Route to Bis(4-spiro-fused-β-lactams)-Based Macrocycles

Variable-Sized bis(4-spiro-fused-β-lactam)-Based Unsaturated Macrocycles: Synthesis and Characterization

The synthesis with structural identifications including NMR and HRMS spectral data along with single-crystal X-ray diffraction analysis (for 20b, 23b, 25b-27b) of a family of 14 new syn/anti bis-4-spiro-β-lactam-based unsaturated macrocycles (19a,b-27a,b), obtained by multistep synthesis including (i) diimine formation, (ii) Staudinger [2 + 2] ketene-imine cycloaddition, and (iii) ring-closing metathesis (RCM), is reported.