Synthesis of the Rubrolone Aglycon

Key words

rubrolone aglycon - tropolone natural product - Stille coupling - cyclopropane ketal - Diels–Alder reaction - norcaradiene rearrangement

Significance

Boger and co-workers report a concise total synthesis of the rubrolone aglycon. To construct the pyridine and the tropolone motifs present in the natural product, the authors based their synthetic strategy on two unusual Diels–Alder reactions.

Comment

The synthesis features an intramolecular hetero Diels–Alder reaction, involving an O-alkyl α,β-unsaturated oxime as diene, to construct the substituted pyridine D. A second Diels–Alder reaction featuring diene F and cyclopropenone ketal G as dienophile gave access to the cycloaddition product H. Upon oxidation and subsequent norcaradiene rearrangement, the tropolone J was accessed.

Publication History

Article published online:
16 January 2024