Abstract
Several chiral polyfunctionalyzed cyclohexanones and cyclohexenones have been synthesized through Diels-Alder cycloadditions, stereoselectivity being stated by X-ray structural analysis and NOE experiments. The chemoselectivity in the palladium(II)-catalyzed reaction between cyclohexenones and diazomethane has been investigated. Thus, in those enones bearing an amide function on the γ-carbon, the preferential addition occurs at the carbonyl giving epoxides which, under acid conditions, rearrange to tetrahydrobenzoxazoles. The other cyclohexenones afford cyclopropanes as a result of addition to the C=C bond. A mechanistic approach to explain the whole process is proposed. © 2001 Elsevier Science Ltd.
Original language | English |
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Pages (from-to) | 1025-1034 |
Journal | Tetrahedron |
Volume | 57 |
Issue number | 6 |
DOIs | |
Publication status | Published - 4 Feb 2001 |
Keywords
- Benzoxazole
- Chemoselectivity
- Cyclohexanones
- Cyclohexenones
- Cyclopropanatio n
- Diazomethane
- Diels-Alder reactions
- Oxiranes
- Palladium diacetate