Platinum catalyzed 7-endo cyclization of internal alkynyl amides and its application to synthesis of the caprazamycin coreThis article is part of the Organic & Biomolecular Chemistry 10th Anniversary issue.Electronic supplementary information (ESI) available: 1H and 13C NMR spectral data and crystallographic data of compound 9 in CIF. CCDC 869849. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c2ob25111f

• Main Authors: Tsukano, Chihiro, Yokouchi, Shinsuke, Girard, Anne-Lise, Kuribayashi, Toshifumi, Sakamoto, Shota, Enomoto, Taro, Takemoto, Yoshiji
• Format: Journal Article
• Language: English
• Published: 14.08.2012
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/c2ob25111f

The scope and limitations of the platinum catalyzed 7- endo cyclization of internal alkynyl amides were investigated. Substitution of the alkyne with an aryl group gave better results, presumably because it stabilized the transition state. Applying the reaction to a secondary amide, the caprazamycin core was successfully synthesized from commercially available material in eight steps. Considering the synthesis of the caprazamycin core, the scope and limitations of platinum catalyzed 7- endo cyclization of internal alkynyl amides were disclosed.