The Application of 1,2-Oxazinanes as Chiral Cyclic Weinreb Amide-Type Auxiliaries Leading to a Three-Component, One-Pot Reaction
作者:Gerhard Hilt、Jan Fährmann、Ludmila Hermann
DOI:10.1055/a-1683-0484
日期:2022.4
1,2-Oxazines were synthesised via a copper-catalysed aerobic acyl nitroso Diels–Alder reaction from 1,4-disubstituted 1,3-dienes and N-Boc-hydroxylamine. From this, 1,2-oxazinanes were obtained in a novel follow-up reaction path. The stability of several 1,2-oxazines and 1,2-oxazinanes towards organometallic compounds was tested to rate their operability as cyclic chiral Weinreb amide auxiliaries.
1,2-恶嗪是通过铜催化的有氧酰基亚硝基 Diels-Alder 反应由 1,4-二取代的 1,3-二烯和 N-Boc-羟胺合成的。由此,在新的后续反应路径中获得了 1,2-恶嗪烷。测试了几种 1,2-恶嗪和 1,2-恶嗪对有机金属化合物的稳定性,以评价它们作为环状手性 Weinreb 酰胺助剂的可操作性。3,6-二叔丁基-1,2-恶嗪烷给出了最好的结果,并作为手性 Weinreb 酰胺型助剂引入,以产生非对映体比例高达 98:2 的手性 α-取代酮。可以用 BuLi 去除助剂以形成不对称的 α-手性酮。此后,手性助剂可以通过真空升华重新分离和纯化。