α-Photooxygenation of chiral aldehydes with singlet oxygen.

Organocatalytic α-oxygenation of chiral aldehydes with photochemically generated singlet oxygen allows synthesizing chiral 3-substituted 1,2-diols. Stereochemical results indicate that the reaction in the presence of diarylprolinol silyl ethers is highly diastereoselective and that the configuration of a newly created stereocenter at the α-position depends predominantly on the catalyst structure. The absolute configuration of chiral 1,2-diols has been unambiguously established based on electronic circular dichroism (ECD) and TD-DFT methods.