17714-42-0Relevant articles and documents
Solvent pressure effects in free radical reactions. A selectivity inversion in free radical brominations induced by solvent
Tanko, James M.,Suleman, N. Kamrudin,Hulvey, Glenn A.,Park, Anna,Powers, Jennifer E.
, p. 4520 - 4526 (1993)
The results reported herein demonstrate a compelling link between selectivity in free radical brominations and the internal pressure of solvent. In a study encompassing 18 solvents and/or solvent mixtures, the rate constant ratio for SH2 ring o
Boron tribromide as a reagent for anti-Markovnikov addition of HBr to cyclopropanes
Chen, Shuming,Gieuw, Matthew H.,Houk, K. N.,Ke, Zhihai,Yeung, Ying-Yeung
, p. 9426 - 9433 (2020/10/02)
Although radical formation from a trialkylborane is well documented, the analogous reaction mode is unknown for trihaloboranes. We have discovered the generation of bromine radicals from boron tribromide and simple proton sources, such as water ortert-butanol, under open-flask conditions. Cyclopropanes bearing a variety of substituents were hydro- and deuterio-brominated to furnish anti-Markovnikov products in a highly regioselective fashion. NMR mechanistic studies and DFT calculations point to a radical pathway instead of the conventional ionic mechanism expected for BBr3
Selective C-H halogenation over hydroxylation by non-heme iron(iv)-oxo
Rana, Sujoy,Biswas, Jyoti Prasad,Sen, Asmita,Clémancey, Martin,Blondin, Geneviève,Latour, Jean-Marc,Rajaraman, Gopalan,Maiti, Debabrata
, p. 7843 - 7858 (2018/10/31)
Non-heme iron based halogenase enzymes promote selective halogenation of the sp3-C-H bond through iron(iv)-oxo-halide active species. During halogenation, competitive hydroxylation can be prevented completely in enzymatic systems. However, synthetic iron(iv)-oxo-halide intermediates often result in a mixture of halogenation and hydroxylation products. In this report, we have developed a new synthetic strategy by employing non-heme iron based complexes for selective sp3-C-H halogenation by overriding hydroxylation. A room temperature stable, iron(iv)-oxo complex, [Fe(2PyN2Q)(O)]2+ was directed for hydrogen atom abstraction (HAA) from aliphatic substrates and the iron(ii)-halide [FeII(2PyN2Q)(X)]+ (X, halogen) was exploited in conjunction to deliver the halogen atom to the ensuing carbon centered radical. Despite iron(iv)-oxo being an effective promoter of hydroxylation of aliphatic substrates, the perfect interplay of HAA and halogen atom transfer in this work leads to the halogenation product selectively by diverting the hydroxylation pathway. Experimental studies outline the mechanistic details of the iron(iv)-oxo mediated halogenation reactions. A kinetic isotope study between PhCH3 and C6D5CD3 showed a value of 13.5 that supports the initial HAA step as the RDS during halogenation. Successful implementation of this new strategy led to the establishment of a functional mimic of non-heme halogenase enzymes with an excellent selectivity for halogenation over hydroxylation. Detailed theoretical studies based on density functional methods reveal how the small difference in the ligand design leads to a large difference in the electronic structure of the [Fe(2PyN2Q)(O)]2+ species. Both experimental and computational studies suggest that the halide rebound process of the cage escaped radical with iron(iii)-halide is energetically favorable compared to iron(iii)-hydroxide and it brings in selective formation of halogenation products over hydroxylation.
Synthesis of 2-alkyl(aryl)thietanes
Volynskii,Shevchenko
, p. 109 - 117 (2008/02/03)
Thietane and its 2-substituted derivatives were synthesized. A general preparation procedure for the synthesis of thietanes bearing alkyl and aryl substituents in the α-position was developed. Using this procedure, 2-substituted thietanes can be obtained from cheap and easily accessible raw materials in three steps. 2-R-Thietanes (where R = H, CH3, C 4H9, C5H11, C6H 13, C6H5) and the corresponding sulfoxides and sulfones were synthesized and examined. Intermediate and by-products of the synthesis were studied. Nauka/Interperiodica 2007.
