Cyclopentanone Synthesis by Intramolecular Carbon-Hydrogen Insertion of Diazo Ketones. A Diterpene-to-Steroid Skeleton Conversion

Article abstract of DOI:10.1021/jo00138a008

Intramolecular carbon-hydrogen insertion on cupric sulfate assisted decomposition of diazomethyl ketones derived from four 1-methylcycloalkanecarboxylic acids and (hexahydrophenyl)acetic, homopivalic, and enanthic acids is shown to yield mostly cyclopentanones.The yields are appreciable in the conformationally favorable cases, and insertion in the solvent cyclohexane can be avoided by the use of Freon TF as the solvent.The conversion of a primaradienic diterpene into a 14-iso-16-androstanone derivative shows the power of the new method of cyclopentanone synthesis.