Lewis Acid Mediated Synthesis of 2-Alkenenitriles Using<i>C</i>,<i>N</i>-Bis(trimethylsilyl)ketenimine and Carbonyl Compounds
作者:Isamu Matsuda、Hisashi Okada、Yusuke Izumi
DOI:10.1246/bcsj.56.528
日期:1983.2
obtained in the condensation reaction of carbonylcompounds with C,N-bis(trimethylsilyl)ketenimine in the presence of Lewis acid. The combination of tris(trimethylsilyl)ketenimine and aldehydes results in the high E-selective formation of 2-trimethylsilyl-2-alkenenitriles. Among some Lewis acids, magnesium bromide gives the best E-selectivity in the formation of 2-trimethylsilyl-2-undecenenitrile. Stereospecific
在路易斯酸的存在下,羰基化合物与 C,N-双(三甲基甲硅烷基)烯酮亚胺的缩合反应得到 2-取代的 2-烯腈。三(三甲基甲硅烷基)烯酮亚胺和醛的组合导致 2-三甲基甲硅烷基-2-烯腈的高 E 选择性形成。在一些路易斯酸中,溴化镁在 2-三甲基甲硅烷基-2-十一烯腈的形成过程中具有最佳的 E 选择性。2-三甲基甲硅烷基-2-烯腈在氟化钾的甲醇水溶液中的立体特异性原脱甲硅烷基化实现了从醛到 (Z)-2-烯腈的新途径。
AN ASYMMETRIC SYNTHESIS OF α-BENZYLOXY ALDEHYDES HAVING A CHIRAL TERTIARY CENTER—AN APPLICATION TO THE ASYMMETRIC SYNTHESIS OF<i>exo</i>-(+)-BREVICOMIN—
作者:Masatoshi Asami、Teruaki Mukaiyama
DOI:10.1246/cl.1983.93
日期:1983.1.5
α-Benzyloxy aldehydes having a chiral tertiary center at α-carbon atom are synthesized in high enantiomeric excess by successive treatment of 2-methoxycarbonyl-3-phenyl-1,3-diazabicyclo[3.3.0]octane with diisobutylaluminum hydride (DIBAL-H) and Grignard reagents. The asymmetric reaction is applied to the total synthesis of exo-(+)-brevicomin.