Palladium-Catalyzed Intramolecular Cyclization of Vinyl and Aryl Triflates. Associated Regioselectivity of the beta-Hydride Elimination Step.
作者:Shaowo Liang、Leo A. Paquette、C. Oliver Kappe、Regis Leung-Toung、Curt Wentrup、Jørgen B. Pedersen、Povl Krogsgaard-Larsen
DOI:10.3891/acta.chem.scand.46-0597
日期:——
Pd(0)-catalyzed intramolecular olefination of vinyl and aryl triflates has been studied with a view to gaining insight into the question of kinetically preferred reductive elimination when at least two options are available. In either series, a non-activated alkene participant was found to be converted most readily into the non-conjugated cyclization product. This trend is seen despite the more forcing conditions
已经研究了Pd(0)催化的乙烯基和芳基三氟甲磺酸酯的分子内烯化反应,以便在至少有两种选择的情况下获得对动力学上优选的还原消除的认识。在任一系列中,发现未活化的烯烃参加者最容易转化成非共轭环化产物。尽管在闭环过程中要使用反应性较低的芳基三氟甲磺酸酯所需的条件更强,但仍可看到这种趋势。另一方面,当侧链由α-丙烯酸甲酯单元终止时,在动力学上优选共轭二烯。这两个反应似乎在能量上紧密平衡,因为产品分布并没有很大的不同。不过,