1,1-Carboboration of Dialkynyltin Compounds using Triorganoboranes of Greatly Different Lewis Acid Strength. 1,4-Stannabora-cyclohexa-2,5-dienes and Characterization of Zwitterionic Intermediates
作者:Bernd Wrackmeyer、Peter Thoma、Simone Marx、Germund Glatz、Rhett Kempe
DOI:10.1002/zaac.201300007
日期:2013.6
stannoles with diethynyltin compounds, whereas the strongly electrophilic B(C6F5)3 leads selectively to 1,4-stannabora-cyclohexa-2,5-dienes for all dialkynyltin compounds studied. In several cases, zwitterionic intermediates could be detected by multinuclear magnetic resonance spectroscopy (1H, 11B, 13C, and 119Sn NMR), and the molecular structure of such an intermediate as well as that of the final
摘要。比较了三有机硼烷 BR3、Et-9-BBN、BPh3 和 B(C6F5)3 对各种二炔基(二有机)锡化合物的反应性(R12Sn(C≡C-R2)2,其中 R12 = –(CH2)5– , R2 = H (a), R1 = nBu, R2 = H (b), R1 = Ph, R2 = H (c), R1 = R2 = nBu (d))。1,1-碳硼化很容易在两个连续的步骤(分子间和分子内)中发生,产生锡醇或 1,4-锡硼-环六-2,5-二烯,或它们的混合物。最弱的路易斯酸性三有机硼烷 BEt3 和 Et-9-BBN 与二炔锡化合物选择性地生成锡醇,而强亲电性 B(C6F5)3 对所有研究的二炔基锡化合物选择性地生成 1,4-锡硼-环六-2,5-二烯. 在一些情况下,两性离子中间体可以通过多核磁共振波谱(1H、11B、13C 和 119Sn NMR)检测到,