Construction and Functionalization of Highly Strained N-Doped Zigzag Hydrocarbon Belts

Abstract

Recent years have witnessed breakthroughs in the study of zigzag hydrocarbon belts. However, the synthesis of heterocycle-containing zigzag molecular belts remains very rare and challenging despite their interesting structures and potential applications in chemistry and materials science. Here, we report the expeditious construction of a highly strained belt [4]arene[4](1,4-dihydropyridine) structure using the fjords-stitching strategy. The synthesis comprised four-fold abnormal m-bromination of four Npivaloylaniline units and Pd2(dba)3/4-Me2NC6H4 PtBu2-catalyzed intramolecular C–N bond-forming reactions. Subsequent functionalization through N-arylations produced a variety of tetraza-embedded octahydrobelt[8]arenes. Further oxidation of p-methoxyphenyl-substituted belt[4]arene[4](1,4-dihydropyridine) with Ag[Al(OtBuF)4] yielded a singlet diradical dication N-doped zigzag belt.