Preparation, properties, and some chemical reactions of phenaleno[1,9-bc]furan

Abstract

The synthesis of hitherto unknown phenaleno[1,9-bc]furan (1), in 11% overall yield from 2-naphthol, has been achieved. Its ¹H and ¹³C n.m.r. spectra have been fully assigned by means of heteronuclear 2D correlations. The furanoid moiety of (1) displays Diels–Alder diene reactivity in its reactions with benzyne, dimethyl acetylenedicarboxylate, and singlet oxygen. The furan ring of (1) also suffers oxidation by m-chloroperbenzoic acid and undergoes catalytic hydrogenation. This chemistry appears to be more characteristic of naphtho[1,2-c]furan than of naphtho[1,2-b]furan although both structural units co-exist in structure (1).