One-pot Formation of Functionalized Cyclopentenone Derivatives via Retro-Benzilic Acid Rearrangement of the Proto-Photocycloadducts of Methyl 2,4-Dioxopentanoate to Methylenecycloalkanes
Synthetic Photochemistry. LX. One-pot Formation of Spirocyclic 3-Acetyl-2-hydroxy-2-cyclopentenone Derivatives from Methylenecycloalkanes and Methyl 2,4-Dioxopentanoate
of proto-photocycloadducts of methyl 2,4-dioxopentanoate to methylenecycloalkanes and -alkenes spontaneously caused retro-benzilic acid rearrangement in high yields. The results are utterly different from those of sterically-crowded acyclic alkenes, with which the rearrangement occurred by thermolysis as a minor process.
Conversions of alkyl allyl and terpenoid allyl ethers in a superbasic medium (dimethyl sulfoxide-potassium hydroxide) are studied. The ethers with an unbranched alkyl substituent isomerize into propenyl ethers, the ethers with a branched unsaturated substituent decompose to give a hydrocarbon, and diallyl ethers isomerize into allyl vinyl ethers whose Claisen rearrangement gives rise to aldehydes.
TROST, B. M.;LAUTENS, M.;PETERSON, B., TETRAHEDRON LETT., 1983, 24, N 42, 4525-4528