Silver(I)-Catalyzed Regioselective Synthesis of Dihydrofuro[3,4-b]quinolines from o-Alkynylquinoline-MBH Adducts and Evaluation of their Photophysical Properties

Abstract

A simple and facile approach is described for the regioselective synthesis of dihydrofuro[3,4-b]quinolines from ortho-alkynylquinoline-Morita-Baylis-Hillman adducts under mild reaction conditions. Interestingly, in case of aromatic alkynes, 5-exo-dig cyclization was observed, while in case of aliphatic long chain alkynes, 6-endo-dig cyclized products were obtained. The present approach does not require any dry conditions, tedious work-up or inert atmosphere for the production of dihydrofuro[3,4-b]quinolines. The exact structures and stereochemistry of the synthesized molecules were assigned by NMR and X-ray crystallographic analysis. Their photophysical properties were also evaluated. © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim