Preparation of five- and six- membered cyclic ketones by the palladium-catalyzed cyclization reaction. Application to methyl dihydrojasmonate synthesis
✍ Scribed by Jiro Tsuji; Yuichi Kobayashi; Hideaki Kataoka; Takashi Takahashi
- Book ID
- 104225495
- Publisher
- Elsevier Science
- Year
- 1980
- Tongue
- French
- Weight
- 220 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
Methyl 3-oxo-S-phenoxy-6-octenoate (1) was cyclized using Pd(OAc)2-PPh3 as a catalyst to give 2-carbomethoxy-3-vinylcyclopentanone (2) and 2-carbomethoxy-4-cycloheptenone (3). The former was the main product in acetonitrile. 2-Alkylated 3-oxo-8-phenoxy-6-octenoates were converted mainly to the five-membered ketones. Based on this cyclization method, methyl dihydrojasmonate (8) was prepared from methyl 2-pentyl-3-oxo-8-phenoxy-6-octenoate (5). Methyl 3-0x0-9phenoxy-7-nonenoate (10) was subjected to the palladium-catalyzed cyclization to afford Z-carbomethoxy-3-vinylcyclohexanone (2) selectively without forming the eight-membered ketone 12.
We had discovered the reaction of n-allylpalladium complex with carbanions as a useful method of carbon-carbon bond formation.