REACTION OF ACETYLENES WITH HYDROGEN-CHLORIDE IN ACETIC-ACID - EFFECT OF STRUCTURE UPON ADE2 AND AD3 REACTION-RATES
REACTION OF ACETYLENES WITH HYDROGEN-CHLORIDE IN ACETIC-ACID - EFFECT OF STRUCTURE UPON ADE2 AND AD3 REACTION-RATES
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DOI：
10.1021/jo00922a024
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发表时间：
1974-01-01
影响因子：
3.6
通讯作者：
LEE, DJ
中科院分区：
文献类型：
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作者：
FAHEY, RC;PAYNE, MT;LEE, DJ
研究了苯乙炔、1-苯丙炔、1-己炔和叔丁基乙炔与HCl在25 ℃醋酸溶液中反应的起始反应速率和产物组成。还考察了50 ℃时HCl加成1-己炔-7-d的立体化学。通过比较AdE_2和抗Ad_3的反应机理，发现结果与反应一致。结果表明，AdE 2和Ad 3的作用机制涉及不同的区域特异性和立体特异性。结构对反应速率的影响在两种机制中被发现是完全不同的，暗示着显著不同的过渡态结构。在先前的论文1 - 6中，我们已经提出了HCl加成到乙酸中的烯烃和乙炔的两种不同机制的证据。通过不饱和化合物的缓慢质子化以形成氯化碳离子对，发生经由AdE 2机制的反应1 - 3。
Studies of the initial reaction rate and product composition for the reaction of phenylacetylene, 1-phenylpropyne, 1-hexyne, and ierf-butylacetylene with HC1 in HOAc at 25 are reported. The stereochemistry of HC1 ad-dition to l-hexyne-7-d at 50 was also examined. The results are found to be consistent with reaction via com-peting AdE2 and anti Ad3 reaction mechanisms. The resultsshow that the AdE2 and Ad3 mechanisms involve different regiospecificity, as well as stereospecificity. The effect of structure upon reaction rate is found to be quite different in the two mechanisms, implicating significantly different transition-state structures.In previous papers1" 6 we have presented evidence for two distinct mechanisms for addition of HC1 toolefins and acetylenes in acetic acid. Reaction via the AdE2 mechanism1" 3 occurs by slow protonation of the unsaturated compound to form a carbonium chloride ion pair in-