Rhodium-Catalyzed Asymmetric 1,4-Shift/Double-Cyclization Cascade for De Novo Synthesis of Spirolactones

A rhodium-catalyzed asymmetric 1,4-shift/double-cyclization cascade of alkyne-tethered ketoesters with arylboronic acids was disclosed. This sequence facilitates the de novo synthesis of chiral spirolactones with high enantioselectivities and allows for the formation of three chemical bonds and two rings in a single step. Moreover, synthetic applications of this protocol have been underscored by diverse transformations that afford versatile chiral spirocycles. Mechanistic studies illustrate that this cascade involves a 1,4-rhodium shift.