Enantioselective synthesis of (–)-barrenazines A and B.

Martínez, M. M.; Sarandeses, L. A.; Pérez Sestelo, J.


Tetrahedron Lett. 2007, 48, 8536–8538 (DOI: 10.1016/j.tetlet.2007.09.145).

trigger text
hidden content

A short enantioselective synthesis of barrenazines A and B is described. Barrenazines A and B are prepared following a common synthetic route in nine steps (19% overall yield) and eight steps (21% overall yield), respectively, from readily available 4-methoxy-3-(triisopropylsilyl)pyridine. The synthesis relies on a highly diastereoselective nucleophilic addition of a Grignard reagent to a chiral acylpyridinium salt, a radical azidation of a silyl enol ether and the assembly of the pyrazine ring by reductive dimerization of a functionalized 5-azidopiperidin-4-one.