2582-56-1Relevant academic research and scientific papers
Cross-coupling strategy for the synthesis of diazocines
Eleya, Nadi,Li, Shuo,Staubitz, Anne
supporting information, p. 1624 - 1627 (2020/03/13)
Ethylene bridged azobenzenes are novel, promising molecular switches that are thermodynamically more stable in the (Z) than in the (E) configuration, contrary to the linear azobenzene. However, their previous synthetic routes were often not general, and yields were poorly reproducible, and sometimes very low. Here we present a new synthetic strategy that is both versatile and reliable. Starting from widely available 2-bromobenzyl bromides, the designated molecules can be obtained in three simple steps.
A well-defined low-valent cobalt catalyst Co(PMe3)4 with dimethylzinc: a simple catalytic approach for the reductive dimerization of benzyl halides
Fallon, Brendan J.,Corcé, Vincent,Amatore, Muriel,Aubert, Corinne,Chemla, Fabrice,Ferreira, Franck,Perez-Luna, Alejandro,Petit, Marc
, p. 9912 - 9916 (2016/12/07)
Herein, we report the first catalytic version of a cobalt-catalysed reductive homocoupling of benzyl halides which proceeds with low catalyst loadings (0.5 to 5 mol%). By synthetizing each cobalt intermediate we demonstrate that reaction proceeds through two single electron transfers (SET) and that dimethylzinc is only involved in the regeneration of the catalytic species.
Straightforward synthesis of substituted dibenzyl derivatives
Mboyi, Clève D.,Gaillard, Sylvain,Mabaye, Mbaye D.,Pannetier, Nicolas,Renaud, Jean-Luc
, p. 4875 - 4882 (2013/06/26)
The C-C bond formation by homogeneous catalysis is a powerful tool in organic synthesis. The replacement of noble metal by cheaper one for already reported methodologies is of interest for an economical purpose. The attractivity of such replacement is also enhanced if a first raw transition metal is found to be active in several processes. This work demonstrates that a common nickel complex can be used for a two-step cross-coupling procedure, namely a homocoupling reaction of benzyl derivatives and a subsequent Suzuki reaction. These consecutive reactions permit the synthesis of new polyfunctionalized dibenzyl compounds.
Iron-catalyzed homo-coupling of simple and functionalized arylmagnesium reagents
Cahiez, Gerard,Chaboche, Christophe,Mahuteau-Betzer, Florence,Ahr, Mathieu
, p. 1943 - 1946 (2007/10/03)
(Chemical Equation Presented) Iron-catalyzed homo-coupling of simple and functionalized arylmagnesium reagents is described. The reaction is highly chemoselective (CN, COOEt and NO2 groups are tolerated). The procedure was used to perform intramolecular couplings. This cyclization reaction is the key step of the total synthesis of the N-methylcrinasiadine.
Flash vacuum pyrolysis over magnesium. Part 1 - Pyrolysis of benzylic, other aryl/alkyl and aliphatic halides
Aitken, R. Alan,Hodgson, Philip K.G.,Morrison, John J.,Oyewale, Adebayo O.
, p. 402 - 415 (2007/10/03)
Flash vacuum pyrolysis over a bed of freshly sublimed magnesium on glass wool results in efficient coupling of benzyl halides to give the corresponding bibenzyls. Where an ortho halogen substituent is present further dehalogenation gives some dihydroanthracene and anthracene. Efficient coupling is also observed for halomethylnaphthalenes and halodiphenylmethanes while chlorotriphenylmethane gives 4,4′-bis(diphenylmethyl)biphenyl. By using α,α′-dihalo-o-xylenes, benzocyclobutenes are obtained in good yield, while the isomeric α,α′-dihalo-p-xylenes give a range of high thermal stability polymers by polymerisation of the initially formed p-xylylenes. Other haloalkylbenzenes undergo largely dehydrohalogenation where this is possible, in some cases resulting in cyclisation. Deoxygenation is also observed with haloalkyl phenyl ketones to give phenylalkynes as well as other products. With simple alkyl halides there is efficient elimination of HCl or HBr to give alkenes. For aliphatic dihalides this also occurs to give dienes but there is also cyclisation to give cycloalkanes and dehalogenation with hydrogen atom transfer to give alkenes in some cases. For 5-bromopent-1-ene the products are those expected from a radical pathway but for 6-bromohex-1-ene they are clearly not. For 2,2-dichloropropane and 1,1-dichloropropane elimination of HCl occurs but for 1,1-dichlorobutane, -pentane and -hexane partial hydrolysis followed by elimination of HCl gives E, E-, E,Z- and Z,Z- isomers of the dialk-1-enyl ethers and fully assigned 13C NMR data are presented for these. With 6-chlorohex-1-yne and 7-chlorohept-1-yne there is cyclisation to give methylenecycloalkanes and -cycloalkynes. The behaviour of 1,2-dibromocyclohexane and 1,2-dichlorocyclooctane under these conditions is also examined. Various pieces of evidence are presented that suggest that these processes do not involve generation of free gas-phase radicals but rather surface-adsorbed organometallic species.
Pd-catalyzed reactions of donor - Acceptor-substituted cyclopropanes and their ring-opened derivatives: Attempted heck cyclization and novel one-pot enolate arylations
Khan, Faiz Ahmed,Czenvonka, Regina,Reissig, Hans-Ulrich
, p. 3607 - 3617 (2007/10/03)
Donor-acceptor substituted cyclopropane derivatives 4a-g were synthesized in good yields from ketones, via the corresponding silyl enol ethers 2a-g, by cyclopropanation with methyl diazoacetate followed by alkylation using o-iodobenzyl iodide. The γ-oxo esters 5a-g were prepared in high yield, employing NEt3·3 HF. A novel Pd-catalyzed one-pot transformation of 4a-f into 1,2-disubstituted indanes 6a-f was accomplished using either CsF (Method A or B) or Bu4NF (Method C) as the fluoride source to achieve the in situ ring-opening of 4a-f. The two reagents CsF and Bu4NF function in a complementary manner. For example, CsF works better with enones 4b and 4c, while Bu4NF functions well with aryl/alkyl ketones 4d-f. Pd-catalyzed Heck cyclization of vinyl ketone 5a furnished mainly the 7-exo-trig cyclization product 7 but isopropenyl ketone 5b gave a moderate yield of indane derivative 6b, arising from enolate arylation. When the carbonyl group in 5b was protected, a novel tricyclic compound 13 was obtained in low yield. Wiley-VCH Verlag GmbH, 2000.
Dehalogenation of organic halides by flash vacuum pyrolysis over magnesium: A versatile synthetic method
Aitken, R. Alan,Hodgson, Philip K. G.,Oyewale, Adebayo O.,Morrison, John J.
, p. 1163 - 1164 (2007/10/03)
Flash vacuum pyrolysis over magnesium at 600°C results in efficient dehalogenation of a variety of organic halides and provides a preparatively useful method for C-C bond formation and other reactions.
