Cobalt(III)-Catalyzed Diastereoselective Three-Component C-H Bond Addition to Butadiene and Activated Ketones.

A highly diastereoselective three-component C-H bond addition across butadiene and activated ketones is described. This transformation provides homoallylic tertiary alcohols through the formation of two C-C σ bonds and with complete selectivity for an E-alkene isomer. The reaction exhibits good scope with respect to activated ketone inputs, including highly strained cyclic and electron-deficient cyclic and acyclic ketones. Additionally, high diastereoselectivities were achieved for alcohols prepared from unsymmetrical ketones.