Stereochemistry and kinetic deuterium isotope effects in the thermal 1,3-sigmatropic rearrangement of (-)-(R,R)-trans-2-methyl-1-(1-tert-butylvinyl)cyclopropane: evidence for a biradical intermediate
作者:Joseph J. Gajewski、James Michael Warner
DOI:10.1021/ja00315a063
日期:1984.2
and heated in the gas phase in a static well-conditioned reactor at 280/sup 0/C. The observed normal isotope effect on the 1,3-shift is in the opposite direction from that usually associated with secondary ..cap alpha.. deuterium isotope effects resulting from changes in bonding, and this inverse isotope effect is thought to arise by induction from the rotational effect on the 1,3-shift. However, the
环丙烷中热诱导的一级 1,3-化学位移的机制尚未明确定义。为了解决 1,3-移位的机理,(-)-(R,R)-trans-2-methyl-1-(1-tert-butylvinyl) cyclopropane 及其 1-(2,2-制备双氘-1-叔丁基乙烯基)衍生物(80% 氘化),并在静态良好条件下的反应器中以 280/sup 0/C 的温度在气相中加热。观察到的对 1,3 位移的正常同位素效应与通常与由键合变化引起的二次 ..cap α.. 氘同位素效应相关的效应相反,并且这种逆同位素效应被认为是由诱导产生的1,3-shift 上的旋转效应。然而,该解释与对映异构化的相对较大的速率常数不一致,除非对映异构化是一个单独的过程。(BLM)