The copper-catalyzed synthesis of ()-2-naphtho[1,8-]thiophenes with solid emission

In recent years, one of the main research interests of our group has been the construction of 6/5 π-systems through the regioselective conversion of parallel alkynes in naphthalene with the aim of exploiting potential fluorescent materials. Herein, the copper-catalyzed synthesis of polysubstituted ( Z )-2 H -naphtho[1,8- bc ]thiophenes from 8-halo-1-ethynylnaphthalenes using potassium ethylxanthate as the sulfur source is reported. In this protocol, a series of thiophene-fused 6/5 π-system compounds was synthesized via copper-catalyzed Ullmann-type C(aryl)-S bond formation and the α-addition of an alkyne bond with high selectivity and in high yields. The synthesized polysubstituted ( Z )-2 H -naphtho[1,8- bc ]thiophenes exhibited solid emission, which made them potential candidates for use in optoelectronic conjugated materials. By using DMSO/D 2 O (3 : 1) as the reaction solvent, the deuterated products could be obtained in good yields under standard conditions. The copper-catalyzed one pot synthesis of polysubstituted ( Z )-2 H -naphtho[1,8- bc ]thiophenes is reported using potassium ethylxanthate as the sulfur source. The synthesized polysubstituted ( Z )-2 H -naphtho[1,8- bc ]thiophenes exhibited solid emission.