Enantioselective One-Pot Synthesis of Cyclopropane-Fused Tetrahydroquinolines via a Ru-Catalyzed Intramolecular Cyclopropanation

Org Lett. 2024 Aug 2;26(30):6502-6506. doi: 10.1021/acs.orglett.4c02416. Epub 2024 Jul 24.

Abstract

A highly enantioselective one-pot synthesis of cyclopropane-fused tetrahydroquinolines bearing carbonyl functionalities, which are difficult to synthesize using conventional methods, is reported. Employing readily accessible alkene-tethered anthranilaldehydes, hydrazone formation and subsequent Ru-catalyzed intramolecular cyclopropanation furnish the desired products in ≤87% yield and ≤95% ee under mild conditions. Various anthranilaldehydes, functionalized alkenes, and N-aryl sulfonyl groups are tolerated, and a series of synthetic transformations were conducted to demonstrate the practical utility.