Stereo‐Controlled Synthesis of Vicinal Tertiary Carbinols: Application in the Synthesis of a Diol Substructure of Zaragozic Acid, Pactamycin and Ryanodol

Abstract

A novel and flexible approach for the stereo‐controlled synthesis of vicinal tertiary carbinols is reported. The developed strategy featured a highly diastereoselective singlet‐oxygen (O21) [4+2] cycloaddition of rationally designed cyclohexadienones (derived from oxidative dearomatization of the corresponding carboxylic‐acid appended phenol precursors), followed by programmed “O−O” and “C−C” bond cleavage. In doing so, a highly functionalized and versatile intermediate was identified and prepared in synthetically useful quantity as a plausible precursor to access a variety of designed and naturally occurring vicinal tertiary carbinol containing compounds. Most notably, the developed strategy was successfully applied in the stereo‐controlled synthesis of advanced core structures of zaragozic acid, pactamycin and ryanodol.