110146-70-8Relevant academic research and scientific papers
Ionizing power of aprotic solvents
Streidl, Nicolas,Mayr, Herbert
, p. 2498 - 2506 (2011)
Rate constants for the heterolysis reactions (SN1) of a series of chloro-diarylmethanes in aprotic solvents (dimethyl sulfoxide (DMSO), acetonitrile, carboxamides, etc.) have been determined conductometrically in the presence of amines or triphenylphosphane, which trap the intermediate ion-pairs and suppress ion recombination. The operation of SN2 mechanisms can be excluded because the observed first-order rate constants become almost independent of the nature of the nucleophilic additive when a certain concentration of nucleophile is exceeded. The heterolysis rate constants are used to calculate nucleofugality parameters Nf and sf for chloride in aprotic solvents according to the linear free-energy relationship lgak (25 °C) = sf(Nf + Ef). Ionizing powers YBnCl of these solvents were calculated according to the Winstein-Grunwald equation. Because the heterolysis rate constants in aprotic solvents correlate only poorly with dielectric constants or empirical solvent parameters such as Gutmann's acceptor numbers or ETN values, the most common solvent polarity parameters do not reliably predict ionization rates in aprotic solvents. The kinetics of the heterolyses of chloro-diarylmethanes in aprotic solvents have been studied conductometrically by suppressing ion recombination with amine additives. In this way it became possible to determine the ionizing power of aprotic solvents and compare them to those of protic solvents. Copyright
Sequential Selective C?H and C(sp3)?+P Bond Functionalizations: An Entry to Bioactive Arylated Scaffolds
Babu, K. Naresh,Masarwa, Ahmad,Massarwe, Fedaa,Shioukhi, Israa
, p. 26199 - 26209 (2021/11/09)
Organophosphonium salts containing C(sp3)?+P bonds are among the most utilized reagents in organic synthesis for constructing C?C double bonds. However, their use as C-selective electrophilic groups is rare. Here, we explore an efficient and general transition-metal-free method for sequential chemo- and regioselective C?H and C(sp3)?+P bond functionalizations. In the present study, C?H alkylation resulting in the synthesis of benzhydryl triarylphosphonium salts was achieved by one-pot, four-component cross-coupling reactions of simple and commercially available starting materials. The utility of the resulting phosphonium salt building blocks was demonstrated by the chemoselective post-functionalization of benzylic C(sp3)?+PPh3 groups to achieve aminations, thiolations, and arylations. In this way, benzhydrylamines, benzhydrylthioethers, and triarylmethanes, structural motifs that are present in many pharmaceuticals and agrochemicals, are readily accessed. These include the synthesis of two anticancer agents from simple materials in only two to three steps. Additionally, a protocol for late-stage functionalization of bioactive drugs has been developed using benzhydrylphosphonium salts. This new approach should provide novel transformations for application in both academic and pharmaceutical research.
Synthesis of tertiary sec-alkylamines by the addition of grignard reagents to N,N-dialkylformamides mediated by Ti(OiPr)4 and Me3SiCl
Tomashenko, Olesya,Sokolov, Viktor,Tomashevskiy, Alexander,Buchholz, Herwig A.,Welz-Biermann, Urs,Chaplinski, Vladimir,De Meijere, Armin
experimental part, p. 5107 - 5111 (2009/06/17)
A number of tertiary sec-alkylamines (22 examples, 29-80% yield) have been prepared according to a simple one-pot procedure by the addition of Grignard reagents to N,N-dialkylformamides in the presence of Ti(OiPr)4 and Me3SiCl. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
