✦ LIBER ✦
Thwarting β-Hydride Elimination: Capture of the Alkylpalladium Intermediate of an Asymmetric Intramolecular Heck Reaction
✍ Scribed by Martin Oestreich; Philip R. Dennison; Jeremy J. Kodanko; Larry E. Overman
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 102 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0044-8249
No coin nor oath required. For personal study only.
✦ Synopsis
In spite of containing three conformationally accessible β-H atoms, palladacycle 1 a is an isolable intermediate in the asymmetric Heck cyclization of 2 a. Although 1 a is stable in the presence of the hydrotriflate salt of 1,2,2,6,6-pentamethylpiperidine, it is converted into the oxindole Heck product when exposed to the more acidic hydrotriflate salt of 2,6-di-tert-butylpyridine. Heck cyclization of 2 b is also believed to proceed by way of a palladacyclic intermediate 1 b, which in this case undergoes β-methoxide elimination. Bn=benzyl.