Aromatic Interactions in Organocatalyst Design: Augmenting Selectivity Reversal in Iminium Ion Activation
作者:Mareike C. Holland、Jan Benedikt Metternich、Constantin Daniliuc、W. Bernd Schweizer、Ryan Gilmour
DOI:10.1002/chem.201500270
日期:2015.7.6
that intermolecular aromatic (CH–π and cation–π) interactions between the incipient iminium cation and the indole ring system is key to rationalising selectivityreversal. This is absent in the N‐methylpyrrole alkylation, thus forming the basis of two competing enantio‐induction pathways. A simple L‐valine catalyst has been developed that significantly augments this interaction.
A highly diastereoselective synthesis of chroman derivatives bearing spirocyclic N,O-acetals skeleton via a one-pot tandem reaction
作者:Yu Zhou、Kai-Da Zhou、Xiao-Ping Xu、Ya-Nan Zhu、Zhen Wu、Shun-Jun Ji
DOI:10.1016/j.tet.2014.10.073
日期:2014.12
A tandemreaction for the synthesis of chroman framework via a one-potreaction of phenol, paraformaldehyde, and 5-benzylimidazolidin-4-one mediated by p-nitrobenzoic acid is described. The chroman derivatives containing spirocyclic N,O-acetal skeleton can be obtained in moderate to good yields (up to 89%) with good to excellent diastereoselectivities (up to >20:1 dr).