Tautomerization-Mediated Molecular Switching Between Six- and Seven-Membered Rings Stabilized by Hydrogen Bonding
作者:Golo Storch、Markus J. Spallek、Frank Rominger、Oliver Trapp
DOI:10.1002/chem.201500524
日期:2015.6.8
1,3,4,6‐Tetraketones typically undergo keto–enol tautomerism forming bis‐enols stabilized by intramolecular hydrogen bonding in two six‐membered rings. However, 1,3,4,6‐tetraketones derived from the terpene ketone camphor and norcamphor exist as isomers with two distinguishable modes of intramolecular hydrogen bonding, namely, the formation of six‐ or seven‐membered rings. The structural requirements
1,3,4,6-四酮通常会发生酮-烯醇互变异构现象,形成双烯醇,并通过两个六元环中的分子内氢键来稳定。但是,源自萜烯樟脑和降樟脑的1,3,4,6-四酮以具有两种不同分子内氢键合模式的异构体存在,即形成六元或七元环。通过合成和比较结构类似物详细研究了迄今未知行为的结构要求。此类1,3,4,6-四酮的两种异构体均在溶液和固态下得到充分表征。有趣的是,它们通过互变异构-旋转级联在溶液中缓慢地相互转化,这在DFT计算中得到了证实。温度和与过渡金属Pd,Rh,