1335227-08-1Relevant articles and documents
Total synthesis of the antitumor antibiotic (±)-streptonigrin: First- and second-generation routes for de novo pyridine formation using ring-closing metathesis
Donohoe, Timothy J.,Jones, Christopher R.,Kornahrens, Anne F.,Barbosa, Luiz C. A.,Walport, Louise J.,Tatton, Matthew R.,O'Hagan, Michael,Rathi, Akshat H.,Baker, David B.
, p. 12338 - 12350 (2014/01/17)
The total synthesis 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 high yielding, with the second-generation approach ultimately furnishing (±)-streptonigrin in 14 linear steps and 11% overall yield from inexpensive ethyl glyoxalate. This synthesis will allow for the design and creation of druglike late-stage natural product analogues to address pharmacological limitations. Furthermore, assessment of a number of chiral ligands in a challenging asymmetric Suzuki-Miyaura cross-coupling reaction has enabled enantioenriched (up to 42% ee) synthetic streptonigrin intermediates to be prepared for the first time.
