Titanium-Catalyzed Vinylic and Allylic CF Bond Activation-Scope, Limitations and Mechanistic Insight
作者:Moritz F. Kuehnel、Philipp Holstein、Meike Kliche、Juliane Krüger、Stefan Matthies、Dominik Nitsch、Joseph Schutt、Michael Sparenberg、Dieter Lentz
DOI:10.1002/chem.201201125
日期:2012.8.20
partially fluorinated alkenes, such as previously unknown (Z)‐1,2‐(difluorovinyl)ferrocene. Mechanistic studies indicate a titanium(III) hydride as the active species, which forms a titanium(III) fluoride by H/F exchange with the substrate. The HDF step can follow both an insertion/elimination and a σ‐bond metathesis mechanism; the E/Z selectivity is controlled by the substrate. The catalysts’ ineffieciency
研究了在各种钛催化剂存在下氟代烯烃的加氢脱氟(HDF)的范围,选择性和机理。优化表明该催化剂需要低空间体积和高电子密度。仲硅烷用作优选的氢化物源。各种各样的底物都能产生部分氟化的烯烃,例如以前未知的(Z)-1,2-(二氟乙烯基)二茂铁。机理研究表明,氢化钛(III)是活性物质,它通过与底物的H / F交换形成氟化钛(III)。HDF步骤可以遵循插入/消除和σ键复分解机制。在Ë / ž选择性由底物控制。通过研究其对第6族氢化物配合物的反应性,合理化了催化剂对氟代丙烯的低效率。