University of York, York, YO10 5DD, UK.
Angew Chem Int Ed Engl. 2019 Sep 23;58(39):13942-13947. doi: 10.1002/anie.201907206. Epub 2019 Aug 13.
A strategy for the synthesis of medium-sized lactones and lactams from linear precursors is described in which an amine acts as an internal nucleophilic catalyst to facilitate a novel cyclisation/ring expansion cascade sequence. This method obviates the need for the high-dilution conditions usually associated with medium-ring cyclisation protocols, as the reactions operate exclusively via kinetically favourable "normal"-sized cyclic transition states. This same feature also enables biaryl-containing medium-sized rings to be prepared with complete atroposelectivity by point-to-axial chirality transfer.
本文描述了一种从线性前体制备中到大内酯和内酰胺的合成策略，其中胺作为内部亲核催化剂促进了新颖的环化/环扩张级联序列。该方法避免了通常与中环环化方案相关的高稀释条件的需要，因为反应仅通过动力学有利的“正常”大小的环状过渡态进行。这一相同的特征还通过点到轴向手性转移使含有联芳基的中到大环能够以完全的对映选择性制备。
