金属钐作用下α,α'-二溴代烷基酮与1,3-二烯的[3+4]环加成反应

α,α'-二溴代万花筒特 环状共轭二烯烃(环戊二烯,呋喃) 在金属钐粉和磺化亚铜(10%)作用下, 高产率地得到[3+4]环加成产物. 与开链共轭二烯烃作用没能得到环加成产物. 却高产率地得到α,α'-二溴代烷基酮自身偶合产物环戊烯酮衍生物 .

The [3+4] cycloaddition of α,α'-dibromoketones and 1,3-dienes promoted by samarium metal

The reactions of α,α'-dibromoketones with 1,3-cyclodienes in the presence of Sm/CuI(10%) in tetrahedrofuran gave the corresponding [3+4] cycloaddition products in good yields. In the case of chain 1,3-dienes, only the coupling product of 1a was obtained.