Preparation of α-Aminobenzylphosphonic Acids with a Stereogenic Quaternary Carbon Atom via Microscopically Configurationally Stable α-Aminobenzyllithiums
作者:Edyta Kuliszewska、Martin Hanbauer、Friedrich Hammerschmidt
DOI:10.1002/chem.200800475
日期:2008.9.26
chlorophosphate/Et(3)N and then Boc-protected (Boc=tert-butoxycarbonyl) at the nitrogen atom. These phosphoramidates were metalated by using sBuLi/N,N,N',N'-tetramethylethylenediamine (TMEDA) to give alpha-aminobenzyllithiums that isomerised to alpha-aminophosphonates in yields of up to 80 % with retention of the configuration at the carbon atom. The intermediate tertiary organolithiums were found to be microscopically
将1-苯基乙胺的对映体用氯代磷酸二乙酯/ Et(3)N磷酸化,然后在氮原子上进行Boc保护(Boc =叔丁氧羰基)。通过使用sBuLi / N,N,N',N'-四甲基乙二胺(TMEDA)将这些氨基磷酸酯金属化,以最高80%的产率异构化为α-氨基膦酸酯的α-氨基苄基锂,同时保留了碳原子上的构型。发现中间叔有机锂在Et(2)O中从-78到0摄氏度在微观上构型稳定。通过使用沸腾的6 M HCl或优选使用Me(3)SiBr /(烯丙基)SiMe(3)来解封保护的α-氨基膦酸酯。当Boc组被二乙氧基次膦基取代时,α-氨基苄基锂中间体即使在-78摄氏度下也部分对映异构,并重排生成具有50%ee(ee =对映体过量)的α-氨基膦酸酯。类似地,由N-Boc保护的氨基磷酸酯衍生自1-(1-萘基)乙基-,1-茚满基-和1,2,3,4-四氢-1-萘胺或1-叠氮茚-和-的对映体和/或对映体将1-叠氮基1,2,3,