Direct Access to 2,3-Disubstituted Amido-Indenones through Annulation of 2-Iodobenzaldehydes with Ynamides

Abstract

In this paper we report the annulation reaction between 2-iodobenzaldehyde derivatives and various ynamides. This palladium-catalyzed reaction leads to rare polysubstituted amino-indenones in good yields with a regioselectivity up to complete. Remarkably, a regiodivergent selectivity has been identified between aryl and alkyl or silyl ynamides, with the first leading mainly to 2-amido-indenones and the second to 3-amido-indenones.

Regioselective Difunctionalization and Annulation of Ynamide

“…A novel method for the synthesis of α/β‐amino indanones 54 / 54′ through the regio‐divergent annulation of 2‐iodobenzaldehyde 53 with ynamides 1 b has been developed (Donnard and co‐workers in 2022, Scheme 26). [39] Interestingly, the substituent in ynamide terminus R 1 group regulates the formation of respective products 54 (R 1 =Ar) or 54′ (R 1 =Alk). The reaction proceeds via the oxidative addition of 53 with Pd 0 ‐species to form the intermediate 53 a , followed by a migratory insertion of 53 a with ynamide 1 b in a regio‐divergent manner to give int‐ 53 b or int‐ 53 b′ .…”

Lewis acid-mediated transformations of 5-acyl-N-fluoroalkyl-1,2,3-triazoles to cyclopentenones, indenones, or oxazoles

“…2- N -substituted indenones can be accessed from ynamides, 12 2-alkynylbenzoyl cyanides, 13 or 2-hydroxy-substituted internal alkynes. 14 2-Amino indenones were also prepared via Au-catalyzed intermolecular oxidation of 2-carbonyl-1-ethynyl benzenes 15 or by co-catalyzed annulation of thioamides with ynamides.…”

Synthesis of 2-amidoindenone derivatives through an ynamide carbosilylation/Houben–Hoesch cyclization 2-step sequence

“…1C). The second one, reported by our group, relies on a palladium-catalyzed Larock-type annulation of o -iodo-benzaldehydes 6 (Fig. 1D).…”