Building -bicyclo[4.4.0]decanes/decenes in complex multifunctional frameworks: the case for antibiotic development.

Covering: 2000 to 2020. trans-Bicyclo[4.4.

Asymmetric Total Synthesis of the Naturally Occurring Antibiotic Anthracimycin.

The first total synthesis of the potent antibiotic anthracimycin was achieved in 20 steps. The synthesis features an intramolecular Diels-Alder reaction to forge the -decalin moiety, and an unprecedented aldol reaction using a complex β-ketoester to provide the tricarbonyl motif. A Stork-Zhao olefination and Grubbs ring closing metathesis delivered the /-diene and forged the macrocycle.

Convenient access to 5-membered cyclic iminium ions: evidence for a stepwise [4 + 2] cycloaddition mechanism.

In situ generation and reaction of novel 5-membered N-tosyl cyclic α,β-unsaturated iminium ions from readily prepared stable precursors is demonstrated. Formal iminium Diels-Alder cycloaddition proceeded in good yield via a stepwise rather than concerted cycloaddition process, confirmed through the isolation of a Mukaiyama-Michael type intermediate. Relative stereochemistry was determined upon subsequent intramolecular cyclisation under Lewis acid catalysis to afford formal endo 5,6-spirobicyclic adducts, as confirmed by crystallography.