Practical Pd(II)-Catalyzed C鈥揌 Alkylation with Epoxides: One-Step Syntheses of 3,4-Dihydroisocoumarins
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- 作者：Guolin Cheng ; Tuan-Jie Li ; Jin-Quan Yu
- 刊名：Journal of the American Chemical Society
- 出版年：2015
- 出版时间：September 2, 2015
- 年：2015
- 卷：137
- 期：34
- 页码：10950-10953
- 全文大小：436K
- ISSN：1520-5126
文摘
Pd(II)-catalyzed ortho-alkylation of benzoic acids with both terminal and internal epoxides affords 3,4-dihydroisocoumarins in one step. The presence of potassium countercations is crucial for this reaction. Monoprotected amino acid ligands significantly promote this reaction, enabling the development of a practical C鈥揌 alkylation reaction using 0.5 mol % Pd catalyst. The inversion of stereochemistry in the C鈥揌 alkylation step is consistent with a redox-neutral SN2 nucleophilic ring-opening process as opposed to a Pd(II)/Pd(IV) pathway.