To access the key Ile-Hpa pseudodipeptide motif in hibispeptins, a series of bidentate carboxamide-based auxiliary groups have been explored to facilitate the palladium-catalyzed arylation of unactivated γ-C(sp3)-H bonds of Ile precursor with aryl iodides. A new pyridylmethylamine-based auxiliary group PR is introduced, which permits the use of more sterically hindered ortho-substituted aryl iodide substrates and can be removed under mild conditions. Pd-catalyzed PR-directed γ-C(sp3)-H arylation enabled the first total synthesis of hibispeptin A.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry