Total Synthesis of (±)-Streptonigrin: De Novo Construction of a Pentasubstituted Pyridine using Ring-Closing Metathesis
作者:Timothy J. Donohoe、Christopher R. Jones、Luiz C. A. Barbosa
DOI:10.1021/ja207835w
日期:2011.10.19
The synthesis of the potent antitumor agent (+/-)-streptonigrin has been achieved in 14 linear steps and 11% overall yield from ethyl glyoxalate. The synthesis features a challenging ring-closing metathesis reaction, followed by elimination and aromatization, to furnish a key pentasubstituted pyridine fragment.
Total Synthesis of the Antitumor Antibiotic (±)-Streptonigrin: First- and Second-Generation Routes for de Novo Pyridine Formation Using Ring-Closing Metathesis
作者:Timothy J. Donohoe、Christopher R. Jones、Anne F. Kornahrens、Luiz C. A. Barbosa、Louise J. Walport、Matthew R. Tatton、Michael O’Hagan、Akshat H. Rathi、David B. Baker
DOI:10.1021/jo402388f
日期:2013.12.20
The totalsynthesis of (±)-streptonigrin, a potent tetracyclic aminoquinoline-5,8-dione antitumor antibiotic that reached phase II clinical trials in the 1970s, is described. Two routes to construct a key pentasubstituted pyridine fragment are depicted, both relying on ring-closing metathesis but differing in the substitution and complexity of the precursor to cyclization. Both routes are short and