Aryl-Substituted Cyclopropyl Acetylenes as Sensitive Mechanistic Probes in the Gold-Catalyzed Hydration of Alkynes. Comparison to the Ag(I)-, Hg(II)-, and Fe(III)-Catalyzed Processes
作者:Georgia Velegraki、Manolis Stratakis
DOI:10.1021/jo401325t
日期:2013.9.6
of vinyl carbocations, provides exclusively the corresponding cyclopropyl methyl ketones. On the other hand, in the Ag(I)- or Fe(III)-catalyzed hydration, a profound vinyl carbocationic character appears in the initially formed metal–alkyne complexes, as judged by the partial (Ag+) or exclusive (Fe3+) formation of allene-type rearrangement products. These findings provide clear evidence for subtle electronic
用金催化的2-苯基或2,2-二苯基环丙基乙炔的水合作用,以敏感的探针追踪乙烯基碳正离子的形成,仅提供相应的环丙基甲基酮。另一方面,在Ag(I)或Fe(III)催化的水合作用中,最初形成的金属-炔烃络合物中会出现深刻的乙烯基碳阳离子特征,这可由部分(Ag +)或排他的(Fe 3 +)形成异戊二烯型重排产物。这些发现为金属-炔配合物(包括Au(I或III),Ag(I),Fe(III)和Hg(II))中的细微电子差异提供了清晰的证据。