钯催化合成噻吩并[2,3-b]噻喃-4-酮类化合物OA北大核心CSTPCD

Thieno[2,3-b]thiopyrans are important core structures found in a variety of natural products and other biologically important molecules with a wide range of biological activities.In this work,a series of thieno[2,3-b]thio-pyran-4-one derivatives was constructed from 1,6-disubstituted group-4-(1,3-dithiolan-2-ylidene)-1-en-5-yn-3-one via palladium-catalyzed cycloaddition reactions.Optimization experiments showed that the best experimental condi-tions were as follows:using Pd(OAc)2(30%,molar fraction)as catalyst,the substrate(1.0 mmol)and K2CO3(1.2 mmol)reacted at 100℃for 8 h in N,N-dimethylformamide(DMF),thieno[2,3-b]thiopyran-4-one derivatives were synthesized with a yield of 87%.The composition and structure has been characterized by menas of nuclear magnetic resonance(1H NMR and 13C NMR)and high resolution mass spectrometer(electrospray ionization)[HRMS(ESI)].The mechanism for the reaction was proposed.The menthod had the advantages of mild conditions,safe operation and higher yields.