Incorporation of an Allene Unit into α‐Pinene via β‐Elimination
Incorporation of an Allene Unit into α‐Pinene via β‐Elimination
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通过 β-消除将丙二烯单元并入 α-蒎烯
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
M. Balci
中科院分区：
文献类型：
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作者：
B. Kilbas;A. Azizoglu;M. Balci
通过2，6，6-三甲基双环[3.1.1]庚-3-酮（9）与肼反应，然后在Et 3 N存在下用I2处理，合成了两种双键异构体3-碘-2，6，6-三甲基双环[3.1.1]庚-2-烯（6 b）和3-碘-4，6，6-三甲基双环[3.1.1]庚-2-烯（11）。在二甘醇二甲醚中用t-BuOK作为碱在220°下处理11导致形成9和6，6-二甲基-4-亚甲基双环[3.1.1]庚-2-烯（12）。对于9的形成，环状丙二烯7被提议作为中间体。在170°下用t-BuOK处理第二异构体6 b产生二烯12和二聚产物17。这种转变的基本机制进行了讨论。基于对丙二烯7和炔15的密度泛函理论（DFT）计算，排除了后者作为中间体的形成。
The two double-bond isomers 3-iodo-2,6,6-trimethylbicyclo[3.1.1]hept-2-ene (6b) and 3-iodo-4,6,6-trimethylbicyclo[3.1.1]hept-2-ene (11) were synthesized by reacting 2,6,6-trimethylbicyclo[3.1.1]heptan-3-one (9) with hydrazine, followed by treatment with I2 in the presence of Et3N. Treatment of 11 with t-BuOK as base in diglyme at 220° resulted in the formation of 9 and 6,6-dimethyl-4-methylidenebicyclo[3.1.1]hept-2-ene (12). For the formation of 9, the cyclic allene 7 is proposed as an intermediate. Treatment of the second isomer, 6b, with t-BuOK at 170° gave rise to the diene 12 and the dimerization product 17. The underlying mechanism of this transformation is discussed. On the basis of density-functional-theory (DFT) calculations on the allene 7 and the alkyne 15, the formation of the latter as the intermediate was excluded.