[3+2] Route to Quaternary Oxaprolinol Derivatives as Masked Precursors of Disubstituted β<sup>3</sup>,β<sup>3</sup>-Amino Aldehyde
作者:Pavlo Shpak-Kraievskyi、Amelle Mankou Makaya、Anne Beauchard、Arnaud Martel、Mathieu Y. Laurent、Gilles Dujardin
DOI:10.1002/ejoc.201500339
日期:2015.6
introduced and was shown to afford chemoselectively a quaternary isoxazolidine derivative (of oxaprolinol-type) without cleaving the N–O isoxazolidine bond. Keeping the aldehyde function masked as a cyclic pseudo-acetal, the liberated oxy-amine function was shown to be available for a pseudo-peptide coupling with various N-protected amino acids. The isoxazolidine ring was opened by a reductive N–O bond cleavage
由带有苯基甘氨醇手性助剂的功能性环状酮硝酮开始形成显示一个或两个季立体中心的双环异恶唑烷。这些产品与一系列富电子和缺电子的偶极亲电子试剂进行立体控制的 1,3-偶极环加成反应。引入了一种新的苯基甘氨醇手性助剂的还原去除方法,并显示出化学选择性地提供了季异恶唑烷衍生物(恶丙醇型),而不会裂解 N-O 异恶唑烷键。将醛功能掩蔽为环状假缩醛,释放出的氧胺功能显示可用于与各种 N 保护氨基酸的假肽偶联。异恶唑烷环通过还原性 N-O 键断裂打开,