The p<i>K</i><sub>a</sub>values of<i>N</i>-aryl imidazolinium salts, their higher homologues, and formamidinium salts in dimethyl sulfoxide
作者:Nicholas Konstandaras、Michelle H. Dunn、Ena T. Luis、Marcus L. Cole、Jason B. Harper
DOI:10.1039/d0ob00036a
日期:——
A series of imidazolinium salts, their six-, seven- and eight-membered homologues, and the related formamidiniumsalts were prepared, and their pKa values were determined in DMSO at 25 °C using the bracketing indicator method. The effect of each type of structural variation on the acidity of each salt was considered, particularly noting the importance of ring size and the effect of the steric and electronic
制备了一系列咪唑啉鎓盐,其六元,七元和八元同系物以及相关的甲ami盐,并使用包围指示剂方法在DMSO中于25°C测定了其p K a值。考虑了每种类型的结构变化对每种盐的酸度的影响,尤其要注意环大小的重要性以及氮的空间和电子性质的影响-芳基取代基。还通过将环状体系与相应的甲ami盐进行比较,探讨了环状结构的影响,并指出了在后者情况下构象柔韧性的重要性。除了允许选择合适的碱基使这些物质去质子化外,预计提供的数据将有助于理解相应碳烯的亲核性和潜在的催化功效。
Reactions of triplet carbenes with sulfides and disulfides: ylide vs. radical formation
作者:A. Alberti、D. Griller、A. S. Nazran、G. F. Pedulli
DOI:10.1021/ja00271a035
日期:1986.5
(Thio)urea Organocatalyst Equilibrium Acidities in DMSO
作者:Gergely Jakab、Carlo Tancon、Zhiguo Zhang、Katharina M. Lippert、Peter R. Schreiner
DOI:10.1021/ol300307c
日期:2012.4.6
Bordwell's method of overlapping indicators was used to determine the pK(a) values of some of the most popular (thio)urea organocatalysts via UV spectrophotometric titrations. The incremental effect of CF3 groups on acidic strength was also investigated. The pic's are in the range of 8.5-19.6. The results may lead to a better understanding of noncovalent organocatalysis and may aid in future catalyst development.
Single electron transfer in reactions of alkyl halides with lithium thiolates
作者:E. C. Ashby、W. S. Park、A. B. Goel、Wei Yang Su
DOI:10.1021/jo00225a041
日期:1985.12
ASHBY, E. C.;PARK, W. S.;GOEL, A. B.;SU, WEI-YANG, J. ORG. CHEM., 1985, 50, N 25, 5184-5193
作者:ASHBY, E. C.、PARK, W. S.、GOEL, A. B.、SU, WEI-YANG