52306-31-7Relevant articles and documents
Sulphide as a leaving group: Highly stereoselective bromination of alkyl phenyl sulphides
Canestrari, Daniele,Cioffi, Caterina,Biancofiore, Ilaria,Lancianesi, Stefano,Ghisu, Lorenza,Ruether, Manuel,O'Brien, John,Adamo, Mauro F.A.,Ibrahim, Hasim
, p. 9042 - 9050 (2019/10/22)
A conceptionally novel nucleophilic substitution approach to synthetically important alkyl bromides is presented. Using molecular bromine (Br2), readily available secondary benzyl and tertiary alkyl phenyl sulphides are converted into the corresponding bromides under exceptionally mild, acid- and base-free reaction conditions. This simple transformation allows the isolation of elimination sensitive benzylic β-bromo carbonyl and nitrile compounds in mostly high yields and purities. Remarkably, protic functionalities such as acids and alcohols are tolerated. Enantioenriched benzylic β-sulphido esters, readily prepared by asymmetric sulpha-Michael addition, produce the corresponding inverted bromides with high stereoselectivities, approaching complete enantiospecificity at -40 °C. Significantly, the reported benzylic β-bromo esters can be stored without racemisation for prolonged periods at -20 °C. Their synthetic potential was demonstrated by the one-pot preparation of γ-azido alcohol (S)-5 in 90% ee. NMR studies revealed an initial formation of a sulphide bromine adduct, which in turn is in equilibrium with a postulated dibromosulphurane intermediate that undergoes C-Br bond formation.
Photoinduced C-N bond cleavage in 2-azido-1,3-diphenyl-propan-1-one derivatives: Photorelease of hydrazoic acid
Klima, Rodney F.,Jadhav, Abhijit V.,Singh, Pradeep N. D.,Chang, Mingxin,Vanos, Christine,Sankaranarayanan, Jagadis,Vu, Mai,Ibrahim, Nazarin,Ross, Elaine,McCloskey, Shaun,Murthy, Rajesh S.,Krause, Jeanette A.,Ault, Bruce S.,Gudmundsdottir, Anna D.
, p. 6372 - 6381 (2008/02/11)
(Chemical Equation Presented) Photolysis of 3-azido-1,3-diphenyl-propan-1- one (1a) in toluene yields 1,3-diphenyl-propen-1-one (2), whereas irradiation of 3-azido-2,2-dimethyl-1,3-diphenyl-propan-1-one (1b) results in the formation of mainly 2,2-dimethyl-1,3-diphenyl-propan-1-one. Laser flash photolysis (308 nm) of 1a,b in acetonitrile reveals a transient absorption (λmax = ～310 nm) due to the formation of radicals 4a and 4b, respectively, which have lifetimes of ～14 μs at ambient temperature. TD-DFT calculations (B3LYP/6-31+G(d)) reveal that the first and second excited states of the triplet ketone (T1K (n,π*) and T2K (π,π*)) in azide 1a are almost degenerate, at ～74 and 76 kcal/mol above the ground state (S0), respectively. Similarly, azide 1b has T1K and T2K 75 and 82 kcal/mol above S0, respectively. The calculated transition state for cleaving the C-N bond is located 71 and 74 kcal/mol above S0 in azides 1a and 1b, respectively. The calculated bond dissociation energies for breaking the C-N bond are 55 and 58 kcal/mol for azides 1a and 1b, respectively, making C-N bond breakage accessible from T 1K in azides 1 at ambient temperature. In comparison, the irradiation of azides 1 in argon matrices at 14 K lead to the formation of the corresponding triplet alkyl nitrenes (1-n), via intramolecular energy transfer from T2K- The characterization of 1-n was supported by isotope labeling, IR spectroscopy, and molecular modeling.
Bismuth(III) Halide-Catalyzed Tandem Aldol-Halogenation Reaction: A Convenient Synthesis of β-Halo Ketones and Esters
Roux, Christophe Le,Gaspard-Iloughmane, Hafida,Dubac, Jacques
, p. 2238 - 2240 (2007/10/02)
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