STUDIES ON PREPARATION AND REARRANGEMENTS OF ALLYLIC AZIDES
STUDIES ON PREPARATION AND REARRANGEMENTS OF ALLYLIC AZIDES
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DOI：
10.1021/jo01349a016
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发表时间：
1966-01-01
影响因子：
3.6
通讯作者：
HEASLEY, VL
中科院分区：
文献类型：
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作者：
VANDERWERF, CA;HEASLEY, VL
报道了3，4-二叠氮-L-丁烯(IV)、反-1，4-二叠氮-2-丁烯(V)、1，4-二叠氮-2-丁烯(VI)、3，4-二叠氮-2，3-二甲基-L-丁烯(VII)和锆烷-1，4-二叠氮-2，3-二甲基-2-丁烯(VIII)的制备和重排反应的研究。反式-1，4-二叠氮基-2-丁烯(V)的重排速度比巴豆基叠氮慢，尽管前者有两个潜在的移动基团。3，4-二叠氮-L-丁烯(IV)的重排速度比-1，4-二叠氮-2-丁烯(V)快，比-甲基烯丙基叠氮慢。IV和V的后排速率降低可能是叠氮基团对过渡态的电子抽离作用所致。C？sl，4-二叠氮基-2-丁烯(VI)的重排比反式异构体慢。这可能是由于顺式异构体过渡态的空间位阻较大所致。3，4-二叠氮-2，3-二甲基-1-丁烯(VII)是一种叔叠氮化物，它的重排速度比伯叠氮化物慢，在所有已研究的烯丙基叠氮化物体系中，次叠氮化物和叔叠氮化物的重排速度都比伯叠氮化物快。Vi中甲基之间的空间相互作用可能阻碍双键的共面性和过渡态的叠氮基重排，从而降低重排的速度。讨论了二叠氮化物的稳定性。在研究过程中，IV和V的平衡混合物剧烈爆炸。这两种化合物被认为是极其危险的。温斯坦和他的同事首先对烯丙基叠氮化合物的重排进行了研究。结果表明，巴豆基叠氮可逆地重排为-甲基烯丙基叠氮，7，7-二甲基烯丙基叠氮可逆地重排为-二甲基烯丙基叠氮。它们还表明，重排速率仅随着溶剂极性的增加而略有增加，并且重排表现出负的活化熵。Le Noble报道了压力对α-和7-甲基烯丙基叠氮平衡的影响。4他假设重排是通过循环过渡态进行的。当发现L，4-二溴-2-甲基-2-丁烯与叠氮化钠反应得到3，4-二叠氮-2-甲基-L-丁烯(I)和另一个怀疑是3，4-二叠氮-3-甲基-L-丁烯(II)的叠氮化合物时，我们对叠氮化合物的排列产生了兴趣。5为了扩大叠氮化物重排的知识并研究烯丙基二叠氮化物的制备和性质，6对
A study of the preparations and rearrangements of the following diazides is reported: 3, 4-diazido-l-butene (IV), trans-1, 4-diazido-2-butene (V),«'sl, 4-diazido-2-butene (VI), 3, 4-diazido-2, 3-dimethyl-l-butene (VII), and Zrans-1, 4-diazido-2, 3-dimethyl-2-butene (VIII). trans-1, 4-Diazido-2-butene (V) rearranges more slowly than crotyl azide althoughthe former has two potentially mobile groups. 3, 4-Diazido-l-butene (IV) rearranges faster than¿ rans-1, 4-diazido-2-butene (V), and slower than-methylallyl azide. The decreased rates of rear-rangement of IV and V may result from the electron-withdrawing effect of the azide group on the transition state. c¿ sl, 4-Diazido-2-butene (VI) rearranges slower than the trans isomer. This may result from greater steric hindrance in the transition state of the cis isomer. The rate of rearrangement of 3, 4-diazido-2, 3-dimethyl-1-butene (VII), a tertiary azide, is slowerthan that of¿ rans-1, 4-diazido-2, 3-dimethyl-2-butene (VIII), a primary azide; in all allylic azide systems that have been studied, the secondary and tertiary azides rearrange more rapidly than the primary ones. Steric interactions between the methyl groups in VII may hinderapproach to coplanarity of the double bond and the rearranging azide groupin the transition state, and a decreased rate of rearrangement results. The stabilities of the diazides are discussed. The equilibrium mixture of IV and V exploded violently duringthe course of the investigation. These two compounds are considered to be extremely dangerous.Winstein and co-workers3 were the first to undertake a study of the rearrangement of allylic azides. They showed that crotyl azide rearranges reversibly to give-methylallyl azide and that 7, 7-dimethylallyl azide rearranges reversibly to give,-dimethylallyl azide. They also demonstrated that the rates of rearrangement increase only slightly with an increase in polarity of the solvent and that the rearrangements exhibit negative entropies of activation. The effect of pressure on the equilibration of a-and 7-methylallyl azide was reported by le Noble. 4 He assumed that the rearrangement occurred through a cyclic transition state. We became interested in therearrangements of azides when it was discovered that l, 4-dibromo-2-methyl-2-butene reacts with sodium azide to give 3, 4-diazido-2-methyl-l-butene (I) and another diazide suspected of being 3, 4-diazido-3-methyl-l-butene (II), in addition to the expected l, 4-diazido-2-methyl-2-butene (III). 5 In an effort to expand the knowledge of azide rearrangements and to study the preparationand the properties of allylic diazides, 6 an investigation of