Synthesis of (±)-Butylcycloheptylprodigiosin

Significance

Butylcycloheptylprodigiosin is isolated from a strain of Streptomyces sp. Y-42 also formed during the fermentation of mutant strains of Streptomyces. The synthesis features a novel method for the appendage of a pyrrole ring to a cycloalkenone and proceeds in 23% overall yield (five steps) versus 1.5% yield (16 steps) for a previous synthesis (A. Fürstner et al. Chem. Eur. J. 2007, 13, 1929).