ol6b02480_si_007.cif (21.56 kB)
AlCl3‑Catalyzed Annulations of Ynamides Involving a Torquoselective Process for the Simultaneous Control of Central and Axial Chirality
dataset
posted on 2016-09-21, 17:22 authored by Yanyan Yang, Hongxu Liu, Cheng Peng, Jie Wu, Jingyi Zhang, Yan Qiao, Xiao-Na Wang, Junbiao ChangA highly torquoselective
process for simultaneous control of central
and axial chirality by the annulation of terminally substituted ynamides
with o-quinone methides is reported. In the presence
of AlCl3, a sequence comprising a [2 + 2] cycloaddition
followed by the torquoselective 4π-electrocyclic ring opening
and 6π-electrocyclic ring closure leads to highly stereoselective
formation of diastereoisomeric 4-amino-2H-chromenes.
Terminally unsubstituted ynamides undergo AlCl3-catalyzed
[4 + 2] cycloaddition with o-quinone methides providing
2-amino-4H-chromenes.