Medium-Sized Heterocycle Synthesis by the Use of Synergistic Effects of Ni-NHC and γ-Coordination in Cycloisomerization
作者:Chun-Yu Ho、Lisi He
DOI:10.1021/jo5008477
日期:2014.12.19
an NHC–NiH catalyst and γ-heteroatom chelation were used together as a basis for 1,n-diene termini differentiation and for nγ-exo-trig (head-to-tail) product selectivity. Heterocycles bearing an exocyclic methylene such as oxepines, thiepines, siloxepines, and oxocanes were synthesized from the corresponding 1,n-dienes by a fine-tuning of the NHC properties. The implication of the underlying hypothesis
本文介绍了一种过渡金属催化中型杂环的不对称环异构化的新方法。一个NHC-NIH催化剂和γ -杂原子螯合的空间和电子效应作为1的基础,一起使用Ñ -二烯末端分化和Ñ γ -外型- TRIG(头-尾)产物选择性。由相应的1,n通过微调NHC的特性获得-Dienes。在竞争实验中进一步证明了潜在假设的含义,在该竞争实验中,优先形成应变的oxepines,而不是其他竞争的oxa /碳环素。在更苛刻的物理条件下和使用合适的NHC配体,在一个罐中将环外亚甲基产物进一步异构化为区域内环烯烃产物。