Labelling studies of the conversion of (5, R1 = R2= Me) to (9) on reaction with methyl lithium are consistent with an intermediate (4, R1= R2 = Me) or a carbenoid with no plane of symmetry through the ring, in which selective migration of Ha (Hb and Hd in (1, R1= R2 = Me)) occurs.
与
甲基锂反应时(5,R 1 = R 2 = Me)转化为(9)的标记研究与中间体(4,R 1 = R 2 = Me)或没有对称平面的类
胡萝卜素一致通过环,在其中发生H a(H b和H d in(1,R 1 = R 2 = Me))的选择性迁移。