Visible light photoredox and Polonovsld-Potier cyclizations for the synthesis of (±)-5-epi-cermizine C and (±)-epimyrtine

TETRAHEDRON LETTERS

卷:57

Article

Benimana, Shami Eden¹  Cromwell, Nicholle E.¹  Meer, Humna N.¹  Marvin, Christopher C.¹ 

[1] Hendrix Coll, 1600 Washington Ave, Conway, AR 72032 USA

关键词: Photoredox catalysis;    Visible light;    Polonovski;    Quinolizidine;    Alkaloid;   

DOI  :  10.1016/j.tetlet.2016.10.007

来源: Elsevier

【 摘 要 】

Quinolizidine alkaloids epi-cermizine C and epimyrtine were synthesized from a common intermediate in 5-6 steps from commercially available materials. The key step involved an allylsilane cyclization with an iminium ion formed by oxidation of a tertiary amine. Oxidative annulation was promoted either catalytically by visible light photoredox catalysis or by stoichiometric Polonovski-Potier conditions. There was a modest difference in diastereoselectivity between the two methods, with photoredox providing the key quinolizidine intermediate in 4.7:1 dr versus 2:1 dr for the Polonovski route. (C) 2016 Elsevier Ltd. All rights reserved.

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