2-cyclopentenone, followed by acidic quench, under kinetic control, leads to different ratios of cis and trans 2,3-disubstituted cyclanones according to ring size. From 2-methyl and 2-phenyl 2-cyclohexenone, the cis isomer is highly predominant (85 to 98%). From 2-methyl 2-cyclopentenone a cis/trans mixture is obtained: the cis isomer only predominates when a bulky reagent (1c) is used (80%); in the other cases
将由芳基或
苯基
硫代
乙腈1a-1c和2形成的
碳负离子试剂共轭添加到
2-甲基和2-
苯基2-
环己烯酮或
2-甲基2-环戊烯酮中,然后在动力学控制下进行酸性淬灭,导致不同的比率的顺式和反式,根据环的大小2,3-二取代cyclanones。由
2-甲基和2-
苯基2-
环己烯酮组成的顺式异构体占主导地位(85%至98%)。由
2-甲基2-环戊烯酮获得顺式/反式混合物:仅当使用大体积试剂(1c)(80%)时,顺式异构体占主导。在其他情况下,将获得接近1:1的混合物。