Functionalization of α-hydroxyphosphonates as a convenient route to<i>N</i>-tosyl-α-aminophosphonates
作者:Tomasz Cytlak、Monika Skibińska、Patrycja Kaczmarek、Marcin Kaźmierczak、Magdalena Rapp、Maciej Kubicki、Henryk Koroniak
DOI:10.1039/c8ra01656a
日期:——
Direct conversion of the α-hydroxyl group by para-toluenesulfonamide to yield α-(N-tosyl)aminophosphonates is reported. α-Aminophosphonates 23a,b–37a,b were obtained from the corresponding α-hydroxyphosphonates 6a,b–21a,b in the presence of K2CO3, via the retro-Abramov reaction of the appropriate aldehydes, 1–5. The subsequent formation of imines with simultaneous addition of diethyl phosphite provided
据报道,通过对甲苯磺酰胺直接转化α-羟基以产生α-( N-甲苯磺酰基)氨基膦酸酯。 α-氨基膦酸酯23a,b–37a,b是在 K 2 CO 3存在下,通过适当的醛1–5的逆阿布拉莫夫反应,从相应的 α-羟基膦酸酯6a,b–21a,b获得的。随后形成亚胺并同时添加亚磷酸二乙酯,从而获得 α-磺酰胺膦酸酯23a,b–37a,b,其非对映选择性比 Pudovik 反应更好。本文提出了这种转变的机制。当利用Cbz N-保护的氮丙啶9a,b和苯丙氨酸类似物12a,b时,观察到分子内取代,导致相应的环氧化物38作为唯一产物,或恶唑烷-2-酮39作为次要产物。在脯氨酸18a,b和丝氨酸21a,b衍生物的情况下没有观察到类似的取代。