Institute of Organic Chemistry, Research Centre for Natural Sciences, 2 Magyar tudósok körútja, H-1117 Budapest, Hungary.
Hevesy György PhD School of Chemistry, Eötvös Loránd University, 1/A Pázmány Péter sétány, H-1117 Budapest, Hungary.
J Org Chem. 2023 May 5;88(9):6182-6191. doi: 10.1021/acs.joc.3c00207. Epub 2023 Apr 26.
Diastereoselective and diastereoconvergent syntheses of 2- and 3-substituted morpholine congeners are reported. Starting from tosyl-oxazatedine and α-formyl carboxylates , base catalysis is utilized to yield morpholine hemiaminals. Their further synthetic elaborations allowed the concise constructions of conformationally rigid morpholines. The observed diastereoselectivities and the unusual diastereoconvergence in the photoredox radical processes seem to be the direct consequence of the avoidance of pseudo A strain between the C-3 substituent and the N-tosyl group and the anomeric effect of oxygen atoms.
本文报道了 2-和 3-取代吗啉同系物的非对映选择性和非对映收敛性合成。以对甲苯磺酰基噁唑烷和α-甲酰基羧酸酯为起始原料，通过碱催化生成吗啉半亚胺。进一步的合成衍生化反应允许简洁地构建构象刚性的吗啉。在光氧化还原自由基过程中观察到的非对映选择性和不寻常的非对映收敛似乎是由于避免了 C-3 取代基和 N-对甲苯磺酰基之间的伪 A 应变以及氧原子的端基效应。
