One-pot and metal-free synthesis of atropisomeric carbazolyl-indoles by a facile [4 + 2]-benzannulation in ethanol and investigation of their photoluminescence property

Abstract

With green ethanol as the sole solvent, a novel metal- and oxidant-free one-pot [4 + 2]-benzannulation method has been developed, contributing to the synthesis of a series of atropisomeric carbazolyl-indoles in good yields through an acid-catalyzed propargylation of 2-alkenyl indoles with 1-indolyl propargylic alcohols, followed by cycloisomerization. A preliminary attempt at atroposelective synthesis of carbazolyl-indoles has been conducted, though the enantioselectivity of the product was not satisfactory. Their photoluminescence properties have also been investigated to further reveal the potential application prospects of these molecules.