The mechanisms by which the complexes CpCoL2 (Cp = C5H5; L = CO or CH2=CH2) mediate the cycloisomerizations of α,δ,ω-enynenes containing allylic ether linkages are probed by DFT methods. The outcomes corroborate experimental results and provide energetic and structural details of the trajectories leading to 3-(oxacyclopentyl or cycloalkyl)furans via the intermediacy of isolable CpCo-η 4-dienes. They comprise initial stereoselective complexation of one of the double bonds and the triple bond, rate-determining oxidative coupling to a triplet 16e cobalta-2-cyclopentene, and terminal double bond docking, followed by stereocontrolled insertion to assemble intermediate cis- and trans-fused triplet cobalta-4-cycloheptenes. A common indicator of the energetic facility of the latter is the extent of parallel alignment of the alkene moiety and its target Co–Cα bond. The cobalta-4-cycloheptenes transform further by β-hydride elimination–reductive elimination to furnish CpCo-η 4-dienes, which are sufficiently kinetically protected to allow for their experimental observation. The cascade continues through cobalt-mediated hydride shifts and dissociation of the aromatic furan ring. The findings in silico with respect to the stereo-, regio-, and chemoselectivity are in consonance with those obtained in vitro.

中文翻译：

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(η 5-环戊二烯基)钴介导的烯-炔-烯型烯丙基炔丙醚环异构化为呋喃的轨迹：DFT 评估

配合物 CpCoL2（Cp = C5H5；L = CO 或 CH2=CH2）介导含有烯丙基醚键的 α,δ,ω-烯炔环异构化的机制通过 DFT 方法进行了探测。结果证实了实验结果，并提供了通过可分离的 CpCo-η 4-二烯的中间体产生 3-（氧杂环戊基或环烷基）呋喃的轨迹的能量和结构细节。它们包括双键和三键之一的初始立体选择性络合、与三重 16e 钴-2-环戊烯的决定速率氧化偶联和末端双键对接，然后立体控制插入以组装中间体顺式和反式融合三重钴-4-环庚烯。后者的能量设施的一个常见指标是烯烃部分与其目标 Co-Cα 键平行排列的程度。钴α-4-环庚烯通过β-氢化物消除-还原消除进一步转化以提供CpCo-η 4-二烯，其在动力学上得到充分保护以进行实验观察。通过钴介导的氢化物位移和芳香呋喃环的解离，级联反应继续进行。关于立体选择性、区域选择性和化学选择性的计算机研究结果与体外获得的结果一致。通过钴介导的氢化物位移和芳香呋喃环的解离，级联反应继续进行。关于立体选择性、区域选择性和化学选择性的计算机研究结果与体外获得的结果一致。通过钴介导的氢化物位移和芳香呋喃环的解离，级联反应继续进行。关于立体选择性、区域选择性和化学选择性的计算机研究结果与体外获得的结果一致。