The value of 2 J P–CO as a diagnostic parameter for the structure and thermal reactivity of carbonyl-stabilised phosphonium ylides
作者:R. Alan Aitken、Youcef Boubalouta、Da Chang、Lee P. Cleghorn、Ian P. Gray、Nazira Karodia、Euan J. Reid、Alexandra M.Z. Slawin
DOI:10.1016/j.tet.2017.09.016
日期:2017.11
A survey of 20 carbonyl-stabilised phosphonium ylides with recently reported X-ray structures shows a strong correlation between the CP to CO torsion angle and the value of 2JP–CO, with high values being associated with an anti configuration and low with syn. Seven new X-ray structural determinations are reported, several for types of ylide not crystallographically characterised before, and these also
对最近报道的X射线结构的20个羰基稳定的磷化氢进行的调查显示,C P到C O的扭转角与2 J P–CO的值之间具有很强的相关性,高值与抗构型相关,而低值与syn。报告了七个新的X射线结构测定结果,其中一些测定了以前没有晶体学表征的叶立德类型,这些也符合该模式。然后将2 J P–CO的值与是否热挤压Ph 3相关联发生PO时会生成200多个叶立德的炔烃,并建立了经验规则,即对于该值大于11 Hz的叶立德,绝不会发生挤出。这用于合理化一些三氧杂环戊基和环状环的异常行为,其中两个提供环炔,在重排后分离为异构的1,3-二烯。该规则还适用于一族新型的高度氟化的叶立德,其在快速真空热解后以良好的产率提供氟化的炔烃。