Synthesis of optically active 2-substituted azetidine-2-carbonitriles from chiral 1-arylethylamine <i>via</i> α-alkylation of <i>N</i>-borane complexes
作者:Eiji Tayama、Nobuhiro Nakanome
DOI:10.1039/d1ra04585g
日期:——
The base-promoted α-alkylation of N-((S)-1-arylethyl)azetidine-2-carbonitriles 3via formation of their N-borane complexes 4 was investigated. For example, treatment of diastereomerically pure borane N-((S)-1'-(4''-methoxyphenyl)ethyl)azetidine-2-carbonitrile complex (1S,2S,1'S)-4b with 1.2 equivalents of LDA at -78 °C followed by 1.3 equivalents of benzyl bromide at -78 °C and warming to room temperature
研究了 N-((S)-1-芳基乙基)氮杂环丁烷-2-甲腈 3 通过形成 N-硼烷配合物 4 的碱促进 α-烷基化反应。例如,在-78℃下用1.2当量的LDA处理非对映体纯硼烷N-((S)-1'-(4''-甲氧基苯基)乙基)氮杂环丁烷-2-甲腈络合物(1S,2S,1'S)-4b ℃,然后在-78℃加入1.3当量的苄基溴并升温至室温,产生α-苄基化(2S,1'S)-5ba,产率72%,(2R,1'S)-5ba,产率2%。提出了这种非对映选择性α-烷基化的机制。我们的方法能够从市售的 (S)-(1-(4-甲氧基苯基)) 开始生产光学活性 2-取代氮杂环丁烷-2-甲腈,例如 α-苄基化 (S)-10a 和 (R)-10a乙)胺。