作者:Haruyasu Asahara、Ayano Sofue、Yasuyuki Kuroda、Nagatoshi Nishiwaki
DOI:10.1021/acs.joc.8b01865
日期:2018.11.16
work being reported here, β-nitrostyrenes bearing an ethoxycarbonyl group at the β-position serve as scaffolds for the synthesis of α,β-difunctionalized alkenes. Nitrocinnamates undergo Michael addition reactions with versatile sp3- and sp2-nucleophiles such as alcohols, Grignard reagents, alkylcopper, and dialkylzinc to afford β-substituted nitroethane derivatives. However, various attempts to obtain
在这里报道的工作中,在β位带有乙氧羰基的β-硝基苯乙烯用作合成α,β-双官能化烯烃的支架。硝基肉桂酸酯与通用的sp 3-和sp 2-亲核试剂(例如醇,格氏试剂,烷基铜和二烷基锌)进行迈克尔加成反应,得到β-取代的硝基乙烷衍生物。但是,由于新引入的sp 3 / sp 2之间的空间排斥,通过亚硝酸消除获得双键的各种尝试均告失败。取代基和硝基妨碍了所需的反共面构象。使用较小的sp-亲核试剂(例如乙炔化锂,氰化钾或三甲基甲硅烷基氰化物)成功克服了该问题。尽管用强碱处理加合物并不能消除亚硝酸,但较弱的三乙胺却能以高收率有效地提供官能化的炔烃和丙烯腈。