82966-18-5Relevant articles and documents
SmI2(H2O)n Reduction of Electron Rich Enamines by Proton-Coupled Electron Transfer
Kolmar, Scott S.,Mayer, James M.
, p. 10687 - 10692 (2017)
Samarium diiodide in the presence of water and THF (SmI2(H2O)n) has in recent years become a versatile and useful reagent, mainly for reducing carbonyl-type substrates. This work reports the reduction of several enamines by SmI2(H2O)n. Mechanistic experiments implicate a concerted proton-coupled electron transfer (PCET) pathway, based on various pieces of evidence against initial outer-sphere electron transfer, proton transfer, or substrate coordination. A thermochemical analysis indicates that the C-H bond formed in the rate-determining step has a bond dissociation free energy (BDFE) of ～32 kcal mol-1. The O-H BDFE of the samarium aquo ion is estimated to be 26 kcal mol-1, which is among the weakest known X-H bonds of stable reagents. Thus, SmI2(H2O)n should be able to form very weak C-H bonds. The reduction of these highly electron rich substrates by SmI2(H2O)n shows that this reagent is a very strong hydrogen atom donor as well as an outer-sphere reductant.
Ambient Moisture Accelerates Hydroamination Reactions of Vinylarenes with Alkali-Metal Amides under Air
Bole, Leonie J.,Davin, Laia,García-álvarez, Joaquín,Hernán-Gómez, Alberto,Hevia, Eva,Kennedy, Alan,Mulks, Florian F.
, p. 19021 - 19026 (2020/09/01)
A straightforward alkali-metal-mediated hydroamination of styrenes using biorenewable 2-methyltetrahydrofuran as a solvent is reported. Refuting the conventional wisdom of the incompatibility of organolithium reagents with air and moisture, shown here is that the presence of moisture is key in favoring formation of the target phenethylamines over competing olefin polymerization products. The method is also compatible with sodium amides, with the latter showing excellent promise as highly efficient catalysts under inert atmosphere conditions.
Catalytic intermolecular hydroaminations of unactivated olefins with secondary alkyl amines
Musacchio, Andrew J.,Lainhart, Brendan C.,Zhang, Xin,Naguib, Saeed G.,Sherwood, Trevor C.,Knowles, Robert R.
, p. 727 - 730 (2017/02/26)
The intermolecular hydroamination of unactivated alkenes with simple dialkyl amines remains an unsolved problem in organic synthesis. We report a catalytic protocol for efficient additions of cyclic and acyclic secondary alkyl amines to a wide range of alkyl olefins with complete anti-Markovnikov regioselectivity. In this process, carbon-nitrogen bond formation proceeds through a key aminium radical cation intermediate that is generated via electron transfer between an excited-state iridium photocatalyst and an amine substrate. These reactions are redox-neutral and completely atom-economical, exhibit broad functional group tolerance, and occur readily at room temperature under visible light irradiation. Certain tertiary amine products generated through this method are formally endergonic relative to their constituent olefin and amine starting materials and thus are not accessible via direct coupling with conventional ground-state catalysts.
