Heck Reaction as Key Step in the Synthesis of Hydrogenated 2‐benzazepin‐1‐ones

Abstract

Two strategies were pursued for the synthesis of 2‐benzazepin‐1‐ones 16 and 17 with an N/O‐acetal or enamide in 3‐position. Establishment of the propionaldehyde substructure first and subsequently the amide moiety via a four step sequence failed to provide amides 11. However the Pd‐catalyzed Heck reaction of 2‐iodobenzamides 13 with allyl alcohol and subsequent reaction of the products 14/15 with acid led to 2‐benzazepin‐1‐ones in a two‐step sequence. Depending on the size of the N‐substituent the 3‐methoxy derivative 16a or the dihydro‐2‐benzazepine 17b was formed.

Metal‐Catalyzed Approaches for the Construction of Azepinones

“…Later, in 2014, Wünsch and Quick demonstrated Pd‐catalyzed Heck reaction approach for the construction of azepinones 51 and 52 from halogen‐substituted benzamides 50 possessing monodentate directing groups and allyl alcohol (Scheme 14). [39] …”

“…Later, in 2014, Wünsch and Quick demonstrated Pdcatalyzed Heck reaction approach for the construction of azepinones 51 and 52 from halogen-substituted benzamides 50 possessing monodentate directing groups and allyl alcohol (Scheme 14). [39] The 2-benzazepin-1-ones 51 and 52 were synthesized from either an O/N-acetal or an enamide in the third position using two different techniques. Initially, 2-iodobenzoic acid 53 was activated with DCC and oxalyl chloride, respectively to get respected secondary amides 54 or 57.…”