Reinvestigation of the reactions of camphorketene: structural evidence for pseudopericyclic pathways.
Reinvestigation of the reactions of camphorketene: structural evidence for pseudopericyclic pathways.
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樟脑烯酮反应的重新研究：伪周环途径的结构证据。
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
Birney Dm
中科院分区：
文献类型：
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作者：
Shumway Ww;Dalley Nk;Birney Dm
测定了异戊烯酮（2）二聚体（3和4）的立体化学。3，20和相关化合物的晶体结构显示基态畸变，其被解释为预示逆环加成形成α-氧代烯酮的平面，假周环过渡态。对于s-Z-甲酰基烯酮（8）的二聚化的过渡结构（10）的B3 LYP/6- 31 G * 优化的几何形状与该机制一致。用醇捕获2显示出与其他α-氧代烯酮相当的选择性。2与苯甲醛的反应的缺乏和烯醇互变异构体的缺乏在樟脑酸衍生物中归因于双环樟脑部分中的角应变。
The stereochemistry of the dimers (3 and 4) of camphorketene (2) have been determined. The crystal structures of 3, 20 and of related compounds show ground-state distortions that are interpreted as prefiguring planar, pseudopericyclic transition states for retro-cycloadditions to form alpha-oxoketenes. The B3LYP/6-31G* optimized geometry for the transition structure (10) for the dimerization of s-Z-formylketene (8) is consistent with this mechanism. Trapping of 2 with alcohols shows selectivity comparable to other alpha-oxoketenes. The lack of reaction of 2 with benzaldehyde and the lack of enol tautomers in camphoric acid derivatives is attributed to angle strain in the bicyclic camphor moiety.