The mechanism of methanol loss from the (M ? H)? ions of cis- and trans-4-methoxycyclohexanol. The application of experiment and theory in concert
作者:Suresh Dua、Mark A. Buntine、Mark J. Raftery、Peter C. H. Eichinger、John H. Bowie
DOI:10.1039/p29960002489
日期:——
in the ion source of a mass spectrometer yields the (M – H)– alkoxide ions exclusively. Both of these ions, on collisional activation, form MeO–, MeO–(H2O) and eliminate MeOH. The loss of methanol forms the base peak of the spectrum, and the structure of this daughter anion is shown to be the alkoxide ion from cyclohex-3-enol for both isomers. Evidence (based on product ion, deuterium labelling and AM1
的去质子化的顺式-和反式-4- methoxycyclohexanol通过HO -在质谱仪中的离子源产生的(M - 1H)-醇盐离子只。这两个离子在碰撞活化后均形成MeO –,MeO –(H 2 O)并消除MeOH。甲醇的损失形成了光谱的基峰,该子阴离子的结构显示为来自环己-3-烯醇的两种异构体的醇盐离子。证据(基于产物离子,氘标记和AM1半经验计算研究)表明,反式异构体中甲醇的损失是通过O的内部S N 2环化而进行的–在四个位置(通过1,4-环氧环己烷物质),然后进行3,4消除。顺式异构体可能发生相似的序列,但是在这种情况下,该方法在能量上不如反式异构体有利。