Platinum(II)-Catalyzed Ethylene Hydrophenylation: Switching Selectivity between Alkyl- and Vinylbenzene Production
摘要:
The series of Pt-II complexes [((x)bpy)Pt(Ph)(THF)][BAr'(4)] ((x)bpy=4,4'-X-2,2'-bipyridyl, X = OMe, Bu-t, H, Br, CO2Et, NO2; Ar' = 3,5-bis(trifluoromethyl)phenyl) are catalyst precursors for ethylene hydrophenylation. The bipyridyl substituent provides a tunable switch for catalyst selectivity that also has significant influence on catalyst activity and longevity. Less electron donating 4,4'-substituents increase the propensity toward styrene formation over ethylbenzene.
Platinum(II)-Catalyzed Ethylene Hydrophenylation: Switching Selectivity between Alkyl- and Vinylbenzene Production
作者:Bradley A. McKeown、H. Emanuel Gonzalez、Max R. Friedfeld、Anna M. Brosnahan、T. Brent Gunnoe、Thomas R. Cundari、Michal Sabat
DOI:10.1021/om400306w
日期:2013.5.13
The series of Pt-II complexes [((x)bpy)Pt(Ph)(THF)][BAr'(4)] ((x)bpy=4,4'-X-2,2'-bipyridyl, X = OMe, Bu-t, H, Br, CO2Et, NO2; Ar' = 3,5-bis(trifluoromethyl)phenyl) are catalyst precursors for ethylene hydrophenylation. The bipyridyl substituent provides a tunable switch for catalyst selectivity that also has significant influence on catalyst activity and longevity. Less electron donating 4,4'-substituents increase the propensity toward styrene formation over ethylbenzene.
On the Dichotomic Reactivity of Lithiated Styrene Oxide: A Computational and Multinuclear Magnetic Resonance Investigation
作者:Vito Capriati、Saverio Florio、Filippo Maria Perna、Antonio Salomone、Alessandro Abbotto、Mohamed Amedjkouh、Sten O. Nilsson Lill
DOI:10.1002/chem.200900834
日期:2009.8.10
used to investigate the configurational stability, reactivity and aggregation states of α‐lithiated styrene oxide in THF at 173 K. NMR studies on α‐lithiated [α,β‐13C2]styrene oxide (also in an enantiomerically enriched form) proved that in THF this oxiranyllithium is mainly present as a solvated monomeric species in equilibrium with a complex mixture of stereoisomeric dimeric aggregates, as well as with
由密度泛函理论计算支持的多核磁共振研究已被协同用于研究 α-锂化氧化苯乙烯在 173 K 时在 THF 中的构型稳定性、反应性和聚集状态。α-锂化 [α,β- 13 C 2 ]氧化苯乙烯(也是对映体富集的形式)证明,在THF中,这种环氧乙烷基锂主要以溶剂化单体物质的形式存在,与立体异构二聚体以及桥接和四聚体的复杂混合物平衡。事实上,一些 C α 一些立体异构体中的锂键部分断裂降低了它们的对称性并使 NMR 光谱复杂化:已检测到两种非对映异构体,每个异构体都有一对非对映体碳原子,在不存在四甲基乙二胺 (TMEDA) 的情况下,锂原子缓慢反转。A ( 13 C, 7 Li)-HMQC 实验来关联7 Li 和13首次进行了各种聚集体的 C 共振。通过自然键分析,证明单体聚集体相对于桥接的 O 配位二聚体聚集体具有较低的类胡萝卜素特性。就浓度、温度和 TMEDA 的存在与否而言,采用合适的实