摘要:
Cyclization reactions of ethyl 2-(2-hydroxyaryl)-2-oxoacetates with ethyl 2,3-butadienoate and allenylsulfone proceeded smoothly in the presence of tertiary phosphine and sodium p-toluenesulfinate (SFTS) to give the corresponding quaternary carbon centered chromans in moderate to good yields under mild conditions, which provides an alternative efficient approach for the synthesis of biologically active chroman products. (C) 2012 Elsevier Ltd. All rights reserved.