Novel preparation of non-racemic 1-[α-(1-azacycloalkyl)benzyl]-2-naphthols from Betti base and their application as chiral ligands in the asymmetric addition of diethylzinc to aryl aldehydes
作者:Jun Lu、Xuenong Xu、Shaozhong Wang、Cunde Wang、Yuefei Hu、Hongwen Hu
DOI:10.1039/b204534f
日期:——
A novel route for the preparation of non-racemic 1-[α-(1-azacycloalkyl)benzyl]-2-naphthols was developed, which involves regioselective N-cycloalkylation of the Betti base with dials in the presence of NaBH3CN to give 1-azacycloalka[2,1-b]oxazine followed by the selective cleavage of a CâO bond with LiAlH4. As a new family of chiral ligands, their application in the enantioselective addition of diethylzinc to aryl aldehydes was tested. The ligands incorporating pyrrolidine and piperidine led to highly efficient asymmetric induction to give products in up to 96% yield and 99% ee.
开发了一种制备非外消旋的1-[α-(1-氮杂环烷基)苯基]-2-萘醇的创新路线,该方法涉及在NaBH3CN的存在下对Betti碱进行区域选择性的N-环烷基化,与二醛反应生成1-氮杂环烷基[2,1-b]噁唑,随后用LiAlH4选择性断裂C–O键。作为一种新的手性配体家族,我们测试了其在二乙基锌对芳基醛进行对映选择性加成中的应用。结合呱啉和哌啶的配体实现了高效的非对称诱导,生成的产物收率高达96%,对映体过量(ee)达到99%。