A Convergent Total Synthesis of (±)-γ-Rubromycin

An expeditious convergent total synthesis affords (+/-)-gamma-rubromycin (1) in 4.4% overall yield. The longest linear sequence is 12 steps from commercial starting materials. The effort highlights a remarkable late-stage oxidative [3 + 2] cycloaddition for construction of the spiroketal, a regioselective carbonyl methylenation, a boron tribromide promoted deprotection, ortho- to para-naphthoquinone spiroketal rearrangement, and a tautomerization sequence.