Enantioselective Total Syntheses of Preussomerins: Control of Spiroacetal Stereogenicity by Photochemical Reaction of a Naphthoquinone through 1,6‐Hydrogen Atom Transfer

We report the enantioselective total syntheses of preussomerins EG₁ , EG₂ , and EG₃ . The key transformation is a stereospecific photochemical reaction involving 1,6-hydrogen atom transfer to achieve retentive replacement of a C-H with a C-O bond, enabling otherwise-difficult control of the spiroacetal stereogenic center.