Progresses of Weinreb Amides in Organic Synthesis

Abstract

N-Methoxy-N-methylamides, now popularly called Weinreb amides (WAs) after their discovery, have surfaced as amides with a difference. This amide has served as an excellent acylating agent for organolithium or organomagnesium reagents and as an effective equivalent for an aldehyde group. These two aspects have been exploited exhaustively in many synthetic strategies. The growing synthetic utility and preparation of the Weinreb amides are reviewed.

Carbon–Carbon Bond Formation by Reaction of Rhodium Azavinylcarbenes with Secondary Amides: Access to Indigo Analogues from Isatins

“…However, the poor electrophilicity of amides attributing to the strong resonance stability of the amide bond results in decreased reactivity toward a nucleophilic attack and limited use as synthetic modules, compared to other carbonyl derivatives. Among these transformations, the carbon–carbon (C–C) bond-forming reactions are especially appealing and, thus, undoubtedly powerful tools for the synthesis of multisubstituted amines found in complex natural products and pharmaceuticals. , Thus, a large number of efforts have been made to increase the reactivity of amides via different types of activations, such as the use of particular substituent-activated amides (like Weinreb amides), activation via imidoyl triflate ion, ,, and transition-metal catalysis. ,, Although great progress has been obtained in this field in recent years, the long-standing difficulty still calls for new methodology for the direct transformations of amides to other valuable molecules.…”