Functional transformation of aldehydes and ketones via homolytic induced decomposition of unsaturated peroxy acetals and peroxy ketals

Abstract

Induced decomposition of unsaturated peroxy acetals prepared from trimethyl orthoformate, dodecanal or 2-methylundecanal and 2,3-dimethyl-2-hydroperoxybut-3-ene, in the presence of ethyl iodoacetate, CCl₄ or dodecanethiol, allowed respectively their iodo-, chloro- and hydro- decarbonylation with yields of over 70%; the same reaction applied to the monoperoxy ketal or diperoxy ketal of cyclohexanone in the presence of ethyl iodoacetate resulted in its functional transformation in methyl 6-iodohexanoate or 1,5-diiodopentane with respective yields of 65 and 40%.

References

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11. Reaction of the aldehyde with trimethyl orthoformate in presence of TsOH yielded, after elimination of methyl formate and excess orthoformate, the raw acetal. Addition of 2,3-dimethyl-2-hydro-peroxybut-3-ene (ref. 6) to the acetal, with continuous distillation of MeOH under vacuum (ref. 5), produced the peroxy acetal. After elimination of TsOH by washing the ethereal solution with sodium carbonate and water, followed by drying over magnesium sulfate, the solvent was removed under vacuum. BEt₃ in hexane was added to a solution of the peroxy acetal and the required atom transfer agent in the reaction solvent (cyclohexane, CHCl₃ or CCl₄) until total disappearance of the peroxy acetal as determined by ¹H NMR spectroscopy. After elimination of the solvent and the low boiling reaction products, the expected product was separated by column chromatography (SiO₂).
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