A convenient procedure for the preparation of 1,2,4,5-tetrahydro-1,4-bezodiazepin-3-(3H)-one derivatives (S)-2 from chiral α-substituted N-n-butyl-N-(o-iodobenzyl)glycinamides (S)-1 has been developed. Seven-membered ring formation occurs through an intramolecular N-arylation catalysed by palladium and bis(phosphine) ligands. The use of chelating bis(phosphines) allows to minimize or entirely suppress carbon-2 racemisation which occurs when a mono(phosphine) ligand is used.
我们开发了一种简便的方法,可以从手性的δ-取代的 N-正丁基-N-(邻
碘苄基)甘
氨酰胺 (S)-1 中制备 1,2,4,5-四氢-1,4-二氮杂卓-3-(3H)-酮衍
生物 (S)-2。在
钯和双(膦)
配体的催化下,通过分子内 N-芳基化作用形成了七元环。使用螯合双(膦)
配体可以最大限度地减少或完全抑制碳-2 消旋化,而在使用单(膦)
配体时,碳-2 消旋化会发生。