Umpolung Pd‐Catalyzed α‐Arylation Reactions in Natural Product Synthesis: Syntheses of (+)‐Xestodecalactone A, (–)‐Curvularin, (+)‐12‐Oxocurvularin and (–)‐Citreofuran

Abstract

AbstractThe syntheses (total and formal) of four phenylacetic acid lactone (PAL) natural products have been accomplished by utilizing a unified strategy of an umpolung Pd‐catalyzed α‐arylation of complex α‐bromo esters and boronic acids under mild reaction conditions. As part of the synthetic approaches to these natural products, it was observed that the mild coupling reaction conditions readily tolerated terminal alkenes, other labile ester functionalities, an α,β‐unsaturated ester moiety, and a protected allylic alcohol, while chemoselectively engaging the α‐bromo ester. The completion of (+)‐xestodecalactone A and (–)‐curvularin coupled with the formal syntheses of (+)‐12‐oxocurvularin and (–)‐citreofuran highlight the umpolung Pd‐catalyzed α‐arylation strategy as a key convergent tactic in complex natural product synthesis.