Stereoselective One-Pot Synthesis of Constrained N,O-Orthogonally Protected <i>C</i>-Glycosyl Norstatines [C(1‘)-Aminoglycosyl-1,3-dioxolan-4-ones]
作者:Andrea Guerrini、Greta Varchi、Arturo Battaglia
DOI:10.1021/jo0608164
日期:2006.9.1
usually with high diastereomeric excesses. Both the sulfinyl group at the nitrogen atom and the acetal moiety of the dioxolanone ring were selectively removed, thus demonstrating the orthogonality of the two protecting groups. In fact, the MeO- induced methanolysis of the acetal group gave the corresponding methyl C-glycosyl-sulfinylamino-isoserinates, while the acid induced removal of the sulfinyl group
已经开发出合成构象受限的C-糖基降他汀类药物的方法。该反应的关键步骤是在二恶唑酮的手性(2 S)-烯酸酯中添加(S)-N-亚磺酰基甲亚胺,该化合物利用Seebach的“ SRS”原理。三取代的C-糖基-α-羟基-β-氨基酸形成为N,O-正交保护的1'-糖基-亚磺酰基氨基-二氧戊环-4-酮,通常具有高的非对映异构体过量。氮原子上的亚硫酰基和二氧戊环环的乙缩醛部分均被选择性除去,从而证明了两个保护基的正交性。事实上,中地球轨道-诱导的乙缩醛的甲醇分解得到相应的C-糖基-亚磺酰基氨基-异丝氨酸甲酯,而酸诱导的亚磺酰基的去除得到了N-去保护的1'-糖基氨基-二氧杂戊环4-酮,在某些情况下会发生一锅碱基诱导的环化反应,产生相应的糖基-β-内酰胺。这允许通过化学相关方法或通过对β-内酰胺进行的NOE实验来评估母体1'-糖基-亚磺酰基氨基-二氧戊环-4-酮的立体化学构型。