198. One-Step Synthesis of Diaza Macrocycles by Rh(II)-Catalyzed [3 + 6 + 3 + 6] Condensations of Morpholines and α-Diazo-β-ketoesters
     Alexandre Homberg, Daniele Poggiali, Mahesh Vishe, Céline Besnard, Laure Guénée, Jérôme Lacour
     Org. Lett. 2019, 21, 687-691

Selective formation of oxonium ylides from morpholines and α-diazo-β-ketoesters was achieved. This was applied to the high-concentration (0.5 M) dirhodium-catalyzed (0.1 mol %) [3 + 6 + 3 + 6] synthesis of 18-membered ring diaza macrocycles (46%–72%). Late-stage functionalization of these derivatives is demonstrated. Mechanistic evidence for a novel (undesired) diazo decomposition pathway is also reported.

DOI : 10.1021/acs.orglett.8b03875 

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