Asymmetric Catalytic Dual-Site Functionalization of Allyl Bromides: Construction of Diverse Heterocyclic Frameworks

Abstract

Despite the widespread use of allyl bromides in organic synthesis, the asymmetric transformation of allyl bromides has been less developed. To date, the asymmetric transformation of allyl bromides has been limited to single-site functionalization, and the development of dual-site asymmetric functionalization remains unexplored. In this work, the unprecedented asymmetric dual-site functionalization of allyl bromides has been realized through an efficient organocatalytic system, overcoming the persistent limitation of single-site transformations. Employing dinucleophiles including 3-aminobenzofurans, 2-aminoindoles, and cyclohexane-1,3-diones, this methodology affords benzofuro[3,2-b]pyridines and α-carbolines in good yields with excellent stereoselectivity. The transformation proceeds via a chemoselective S_N2′ pathway mediated by a chiral pyrrolidinyl sulfonamide catalyst, which generates ammonium salts in situ to achieve stereocontrol. The protocol was successfully extended to enantioenriched privileged pyran frameworks, and was applied to diverse downstream transformations. Gram-scale synthesis maintained high enantioselectivity, confirming practical utility. This approach effectively addresses key challenges in efficient construction of complex fused-ring heterocycles, substantially expanding the synthetic applications of allyl bromides.

Keywords

Cyclic allyl bromide / Benzofuro[3,2-b]pyridine / α-Carboline / Pyran / Dinucleophile / Asymmetric catalysis / Organocatalysis / Diastereoselectivity / Enantioselectivity

RIGHTS & PERMISSIONS

2025 SIOC, CAS, Shanghai, & WILEY-VCH GmbH.