Photocatalytic Synthesis of para-Peroxyquinols: Total Synthesis of (±)-Stemenone B and (±)-Parvistilbine B

A photocatalytic method to selectively synthesize 4-hydroperoxy-2,5-cyclohexadienones from para-alkyl phenols is disdosed. This photosensitized singlet oxygen approach functionalized a variety of electronically diverse para-alkyl phenols in 27-99% isolated yields. Utilizing this dearomative oxidation, (+/-)-stemenone B and (+/-)-parvistilbine B were synthesized in 9 and 11 steps, respectively, from commercially available starting materials. Additional experiments revealed the dramatic influence of base and solvent on the selectivity while providing insight into the mechanism of this transformation.

Automated summary

A photocatalytic method for selectively synthesizing 4-hydroperoxy-2,5-cyclohexadienones from para-alkyl phenols with yields ranging from 27% to 99% was reported. By utilizing this approach, (+/-)-stemenone B and (+/-)-parvistilbine B were synthesized in 9 and 11 steps, respectively, from commercially available starting materials. Furthermore, the influence of base and solvent on selectivity was investigated, providing insights into the mechanism of this transformation.