Synthesis of a Novel Taxa‐Oxa‐Sugar Hybrid Core Structure by Tandem Cross‐Enyne Metathesis/IMDA

This paper describes our design and efforts in synthesizing new scaffolds with taxol‐eleutherobin hybrid core structures and a taxol‐sugar hybrid. The synthesis of taxol‐eleutherobin hybrids involved the synthesis of the A‐ring fragment from carvone and the C‐ring fragment from either D ‐mannose or D ‐glucose. The Shapiro reaction was used as the key reaction to couple the A‐ and C‐ring fragments of these hybrid structures. Unfortunately, another key reaction (RCM) failed to form the B‐ring and essentially the core unit. However, a tandem enyne cross‐metathesis/intramolecular Diels–Alder strategy was utilized for the synthesis of a taxa‐oxa‐sugar hybrid.