Synthesis of Polysubstituted Naphthofurans and Indenofurans Based on a Regiodivergent Intramolecular Carbometalation Strategy with 2‐(2’‐Alkynylaryl)‐3‐iodofurans

Abstract

AbstractEfficient methods for the synthesis of two types of furan‐fused tricyclic compounds were developed based on a regiodivergent intramolecular carbometalation strategy using 2‐(2’‐alkynylaryl)‐3‐iodofurans as a common substrate. The iodine‐magnesium exchange/copper‐mediated 6‐endo‐anti intramolecular carbometalation sequence followed by nucleophilic substitution or palladium‐catalyzed cross‐coupling provided 2,3,4,5‐tetrasubstituted naphtho[1,2‐b]furans. On the other hand, the formal intramolecular 5‐exo‐anti carbopalladation/cross‐coupling sequence afforded 2,3‐disubstituted 4‐alkylidene‐4H‐indeno[1,2‐b]furans. The present methods provide new access to a wide range of well‐organized polysubstituted naphtho[1,2‐b]furans and indeno[1,2‐b]furans in a positional selective manner that are otherwise difficult to access.