Effective Synthesis of Aryl Ethers and Coumaranones Employing the Palladium-Catalyzed Enyne−Diyne [4 + 2] Cycloaddition Protocol
作者:Vladimir Gevorgyan、Long Guo Quan、Yoshinori Yamamoto
DOI:10.1021/jo991519k
日期:2000.1.1
degrees C! One-pot consecutive benzannulation of alkyl-substituted enynes 1d,e and alkoxy-substituted enynes 1f,g with alkoxy-substituted diynes 2c and 6 followed by protonolysis with TsOH afforded coumaranones 9a-c and 10 in reasonable to high overall yields.
在Pd(PPh(3))(4)催化剂存在下,烷基,烷氧基和芳氧基取代的共轭炔1顺利进行了区域特异性的[4 + 2]环加成反应,与共轭烷基和烷氧基取代的对称二炔2得到高至高收率的多取代的芳基醚3。在炔属末端具有烷基和烷氧基的不对称二炔6的苯炔环化1d-g,在大多数情况下产生芳族产物8,其中二炔的烷氧基连接到芳族产物的乙炔基部分。值得注意的是,烷氧基取代的二炔2c和6在1℃的异常低温下与1进行了苯甲环化反应!烷基取代的炔烃1d,e和烷氧基取代的炔烃1f的一锅连续连续苯环