Gold(i) and platinum(ii) switch: a post-Ugi intramolecular hydroarylation to pyrrolopyridinones and pyrroloazepinones

Abstract

A regioselective approach for the synthesis of pyrrolopyridinones and pyrroloazepinones is reported employing an Ugi reaction followed by a gold(I) or platinum(II) catalyzed intramolecular hydroarylation.

Gold‐Catalyzed Cycloisomerizations of Functionalyzed Cyclopropyl Alkynes: the Cases of Carboxamides and Alcohols

“…[15] In all these transformations, the combination IPrAuCl/AgOTs proved to be the best catalyst system. [22] Interestingly, the gold-catalyzed synthesis of azepinone derivatives has some precedents, for instance, in the preparation of pyrroloazepinones [23] and azepino- [c,d]indolones. [17] At this point it is worth to note that the azepin-2one skeleton is present in both natural and synthetic products displaying useful biological and pharmaco-logical activities, such as natural and synthetic ceratamines 9-11 (antimicotic and microtubule-stabilizing properties), [18] synthetic compound 12 (inhibitor of gsecretase), [19] zatebradine 13 (specific bradycardic agent), [20] or allsterpaullone 14 (promising candidate for therapeutic treatment of type-1 diabetes) [21] (Figure 2).…”

Au‐ and Pt‐Catalyzed CH Activation/Functionalizations for the Synthesis of Heterocycles

“…In 2012, Van der Eycken and coworkers realized a regioselective synthesis of pyrrolopyridinones 137 and pyrroloazepinones 138 (Scheme 12.60) [64]. They employed an Ugi reaction, which is followed by a gold(I)-or platinum(II)-catalyzed intramolecular hydroarylation.…”

Are Boryl Radicals from Amine–Boranes and Phosphine–Boranes the Most Stable Radicals?

“…Padwa and co‐workers reported an elegant approach comprising the gold‐catalyzed cycloisomerization of N ‐propargylindole‐2‐carboxamides and showed its application in the synthesis of Lavendamycin analogues 6. We recently reported a sequential Ugi/gold‐catalyzed intramolecular hydroarylation approach for the synthesis of various fused heterocycles such as indoloazocines, spiroindolines, indoloazepinones, and pyrrolopyridinones 7–9. Inspired by this work and as a result of our interest in the application of transition‐metal catalysis10 and multicomponent reactions11 for the synthesis of diversely substituted heterocycles, we elaborated a sequential post‐Ugi intramolecular hydroarylation approach to pyrrolopyridines and azepinoindoles 4…”