Jarowski P D, Wodrich M D, Wannere C S, Schleyer P V R, Houk K N
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA.
J Am Chem Soc. 2004 Nov 24;126(46):15036-7. doi: 10.1021/ja046432h.
The conjugation stabilization energies of dienes and diynes are considerably larger than estimates based on heat of hydrogenation differences between 1,3-butadiyne and 1-butyne as well as between 1,3-butadiene and 1-butene. Such comparisons do not take into account the counterbalancing hyperconjugative stabilization of the partially hydrogenated products by their ethyl groups. When alkyl hyperconjugation is considered, the conjugation stabilization of diynes ( approximately 9.3 kcal/mol) is found by two methods (involving isomerization of nonconjugated into conjugated isomers and heats of hydrogenation) to be larger than that of dienes ( approximately 8.2 kcal/mol).
二烯烃和二炔烃的共轭稳定能比基于1,3 - 丁二炔与1 - 丁炔以及1,3 - 丁二烯与1 - 丁烯之间氢化热差异的估计值要大得多。这样的比较没有考虑到部分氢化产物中乙基的超共轭稳定作用的平衡。当考虑烷基超共轭时，通过两种方法（涉及非共轭异构体向共轭异构体的异构化以及氢化热）发现二炔烃的共轭稳定能（约9.3千卡/摩尔）大于二烯烃的共轭稳定能（约8.2千卡/摩尔）。
