期刊
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
卷 57, 期 46, 页码 15177-15182出版社
WILEY-V C H VERLAG GMBH
DOI: 10.1002/anie.201810026
关键词
alkaline earth metals; alkenes; DFT calculations; hydrogenation
资金
- Deutsche Forschungsgemeinschaft (DFG) [HA 3218/9-1]
- FWO [12F4416N]
- VUB
- Vrije Universiteit Brussel
- Flemish Supercomputer Center (VSC)
- FWO
Alkaline earth metal amides (AeN ''(2): Ae = Ca, Sr, Ba, N '' = N(SiMe3)(2)) catalyze alkene hydrogenation (80-120 degrees C, 1-6 bar H-2, 1-10 mol% cat.), with the activity increasing with metal size. Various activated C=C bonds (styrene, p-MeO-styrene, alpha-Me-styrene, Ph2C=CH2, trans-stilbene, cyclohexadiene, 1-Ph-cyclohexene), semi-activated C=C bonds (Me3SiCH=CH2, norbornadiene), or non-activated (isolated) C= C bonds (norbornene, 4-vinylcyclohexene, 1-hexene) could be reduced. The results show that neutral Ca or Ba catalysts are active in the challenging hydrogenation of isolated double bonds. For activated alkenes (e.g. styrene), polymerization is fully suppressed due to fast protonation of the highly reactive benzyl intermediate by N '' H (formed in the catalyst initiation). Using cyclohexadiene as the H source, the first Ae metal catalyzed H-transfer hydrogenation is reported. DFT calculations on styrene hydrogenation using CaN ''(2) show that styrene oligomerization competes with styrene hydrogenation. Calculations also show that protonation of the benzylcalcium intermediate with N '' H is a low-energy escape route, thus avoiding oligomerization.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据