Convergent and Stereodivergent Synthesis of Complex 1-Aza-7-oxabicyclo[2.2.1]heptanes
作者:Dexi Yang、Glenn C. Micalizio
DOI:10.1021/ja202900h
日期:2011.6.22
A convergent and stereodivergent pathway to highly substituted 1-aza-7-oxabicyclo[2.2.1]heptanes is described. It begins with a coupling reaction involving allylic alcohol, aldehyde, and LiHMDS to produce stereodefined primary homoallylic amines. Subsequent N-oxidation and condensation with formaldehyde or glyoxylate defines a convenient entry to densely functionalized homoallylic nitrones whose intramolecular
描述了高度取代的 1-aza-7-oxabicyclo[2.2.1] 庚烷的收敛和立体发散途径。它从涉及烯丙醇、醛和 LiHMDS 的偶联反应开始,以产生立体定义的伯高烯丙基胺。随后的 N-氧化和与甲醛或乙醛酸酯的缩合定义了一种方便的进入密集功能化的同位烯丙基硝酮,其分子内环化可以被控制以提供两个不同的杂环骨架中的一个,每个具有≥20:1 的立体选择。这些反应中立体化学的控制来自于硝酮几何结构的控制和反应途径在直接 [3 + 2] 环加成和串联 [3,3] 重排/[3 + 2] 环加成之间的选择性分配。