Betti reaction of 2-naphthol, furfural, and acetamide: an unexpected case of secondary carbo-Piancatelli rearrangement

Abstract

[Figure not available: see fulltext.] Condensation of 2-naphthol, furfural, and acetamide in the presence of boric acid as acidic catalyst has led to Betti product N-[furan-2-yl(2-hydroxynaphthalen-1-yl)methyl]acetamide along with a new 10,10-dihydrocyclopenta[b]naphtho[1,2-d]furan derivative, which resulted from rare carbo-Piancatelli rearrangement. The structure is confirmed by 1 H, 13 C NMR, HRMS, and X-ray analyses. Mechanism of the transformation is discussed.