Indoles and 1,4-benzodiazepin-2-ones are important heterocyclic scaffolds that feature prominently in pharmaceuticals and bioactive molecules. Developing concise, scalable, and functionally tolerant synthetic routes to these motifs remains an important challenge in synthetic and medicinal chemistry. This presentation describes two complementary, metal-free approaches that enable rapid access to structurally diverse indole and benzodiazepine derivatives from readily available glyoxylate precursors.
First, we report an intramolecular C2–C3 bond-forming annulation of amidophenylglyoxylate derivatives mediated by Lawesson’s reagent, providing direct access to 2,3-disubstituted indoles. The method exhibits broad substrate scope, good functional group tolerance, and scalability to gram quantities. Mechanistic studies support a McMurry-like carbonyl coupling pathway proceeding under metal-free conditions.
Second, a modular strategy to 1,4-benzodiazepin-2-ones is presented, involving coupling of N-protected amino acids to isatins, ring opening to N-glyoxyl esters or amides, followed by deprotection and base-promoted cyclization. This approach enables systematic variation at the C3 and C5 positions and has been demonstrated across a broad library of derivatives.
Together, these methodologies provide practical, scalable routes to important heterocycles and offer versatile platforms for rapid analogue generation in medicinal chemistry programs.