One-pot tandem synthesis of fluorescent 5-naphthyl-3(2H)-furanones

Fluorescent 3(2H)-furanones, 4-cyano-2,2-dialkyl-5-(1- or 2-)naphthyl-3(2H)-furanones, have been synthesized in 69-81% yield by a one-pot procedure, via the tandem reaction of tertiary cyanopropargylic alcohols with 1- and 2-naphthoic acids under mild transition-metal free conditions (Et3N, 20-25 °C for 48-192 h or 55-60 °C for 7-13 h, MeCN). The synthesized compounds fluoresce in the visible region (λmax=419-431 nm), thus being prospective fluorescent biolabels.