Regioselective Synthesis of 3-Bromoquinoline Derivatives and Diastereoselective Synthesis of Tetrahydroquinolines via Acid-Promoted Rearrangement of Arylmethyl Azides

Abstract

Regioselective synthesis of 3-bromoquinoline derivatives was achieved via a formal [4 + 2]-cycloaddition between N-aryliminium ion, generated from arylmethyl azides, and 1-bromoalkynes. This method could also be applied to other quinoline derivatives using appropriate alkynes. Moreover, the current strategy could be utilized for the diastereoselective synthesis of tetrahydroquinoline derivatives employing alkenyl substrates in good to excellent yields.

Crystal structure of (Z)-2-((2-bromo-1-phenylvinyl)oxy)benzonitrile, C15H10BrNO

“…In recent years, bromoalkynes have emerged as versatile and useful building blocks in a variety of synthetic transformations, which can be generally designed as a dual functionalized molecules and di erent reaction intermediates to synthesize all kinds of new compounds with other organic molecules [1][2][3][4]. Bond lengths and bond angles within the molecular system are in agreement with the values reported [5,6].…”

Recent Advances in Reactions of Azides

“…As reported by Tummatorn et al, these N ‐aryliminium ion intermediates were used in the regioselective synthesis of 3‐bromoquinoline derivatives through a formal [4+2] cycloaddition. This method could also be applied to other quinolone derivatives using appropriate alkynes.…”

Synthesis of 3‐Iodoquinolines by Copper‐Catalyzed Tandem Annulation from Diaryliodoniums, Nitriles, and 1‐Iodoalkynes

“…In this method, the cycloaddition of the triple bond was accompanied by a highly regioselective introduction of an iodine atom on the 1,2,3‐triazole ring 13. However, 1‐iodoalkyne 4 was rarely applied in the synthesis of the other heterocycles during the past years 14,15. This phenomenon may arise from two reasons: (i) 1‐iodoalkyne 4 structurally is an internal alkyne, but its behavior is more like that of a terminal alkyne in copper‐catalyzed cycloadditions.…”