Photochemische Primärreaktionen α‐verzweigter aliphatischer Ketone und Aldehyde in lösung

UV.‐Irradiation of methyl t‐butyl ketone, di‐t‐butyl ketone, pivalaldehyde and isobutyraldehyde in benzene solution leads to chemically induced dynamic nuclear polarization (CIDNP.) of the parent compounds and of various reaction products. CIDNP.‐effects and product distributions establish type I α‐cleavage predominantly of triplet state molecules as the major primary photochemical step for all the four α‐branched carbonyl compounds. In chlorinated solvents singlet reactions interfere with the triplet processes.