103304-48-9Relevant academic research and scientific papers
RADICAL REACTIONS IN SYNTESIS. HOMOLYSIS OF ALKYL COBALT SALOPHENS IN THE PRESENCE OF RADICAL TRAPPING AGENTS.
Patel, Vinod F.,Pattenden, Gerald
, p. 1451 - 1454 (1987)
Photolytic homolysis of the alkyl cobalt 'salophens' (10), (20a) and (20b) in the presence of radical trapping agents e.g.O2, TEMPO, NO, SO2, PhSSPh, PhSeSePh, MeSO2Cl, BrCCl3 and I2, leading to oxygen, nitrogen, sulphur, selenium and halogen functionalised products, is used to demonstrate the versatility of cobalt mediated radical reactions in synthesis.
A new family of nucleophiles for photoinduced, copper-catalyzed cross-couplings via single-electron transfer: Reactions of thiols with aryl halides under mild conditions (O C)
Uyeda, Christopher,Tan, Yichen,Fu, Gregory C.,Peters, Jonas C.
supporting information, p. 9548 - 9552 (2013/07/19)
Building on the known photophysical properties of well-defined copper-carbazolide complexes, we have recently described photoinduced, copper-catalyzed N-arylations and N-alkylations of carbazoles. Until now, there have been no examples of the use of other families of heteroatom nucleophiles in such photoinduced processes. Herein, we report a versatile photoinduced, copper-catalyzed method for coupling aryl thiols with aryl halides, wherein a single set of reaction conditions, using inexpensive CuI as a precatalyst without the need for an added ligand, is effective for a wide range of coupling partners. As far as we are aware, copper-catalyzed C-S cross-couplings at 0 C have not previously been achieved, which renders our observation of efficient reaction of an unactivated aryl iodide at -40 C especially striking. Mechanistic investigations are consistent with these photoinduced C-S cross-couplings following a SET/radical pathway for C-X bond cleavage (via a Cu(I)-thiolate), which contrasts with nonphotoinduced, copper-catalyzed processes wherein a concerted mechanism is believed to occur.
Intramolecular carbolithiation of allyl o-lithioaryl ethers: A new enantioselective synthesis of functionalized 2,3-dihydrobenzofurans
Barluenga, Jose,Fananas, Francisco J.,Sanz, Roberto,Marcos, Cesar
, p. 5397 - 5407 (2007/10/03)
A new and easy method for the diastereoselective synthesis of 3-functionalized 2,3-dihydrobenzofuran derivatives from allyl 2-bromoaryl ethers is described. The key step of this transformation involves an intramolecular carbolithiation reaction of allyl 2-lithioaryl ethers. The substituents in both the allyl and the aryl moieties play an important and decisive role in stopping the reaction at the benzofuran thus avoiding a γ-elimination reaction. Finally, this process is amenable to the synthesis of enantiomerically enriched compounds by using ( - )-sparteine as a chiral inductor.
The samarium grignard reaction. In situ formation and reactions of primary and secondary alkylsamarium(III) reagents
Curran, Dennis P.,Totleben, Michael J.
, p. 6050 - 6058 (2007/10/02)
This work shows that primary and secondary radicals are rapidly reduced in THF/HMPA to form primary- and secondary-alkylsamarium reagents. The primary- and secondary-radicals can be formed either by direct SmI2 reduction of primary- and secondary-halides or by a previous rapid radical cyclization. The samarium reagents have moderate stability in solution, and they react with a variety of typical electrophiles, including aldehydes and ketones. The work further shows that organosamarium intermediates can be involved in the traditional samarium Barbier reaction of aldehydes and ketones conducted in THF/HMPA. A new procedure called the "samarium Grignard" method is introduced, and it is suggested that this new procedure will have considerably more scope and generality than the samarium Barbier reaction.
Free Radical Reactions in Synthesis. Homolysis of Alkylcobalt Complexes in the Presence of Radical-Trapping Agents
Patel, Vinod F.,Pattenden, Gerald
, p. 2703 - 2708 (2007/10/02)
Irradiations of the alkylcobalt salophen complexes (14), (21), (22), and (23) in the presence of radical-trapping agents, e.g. molecular oxygen, tetramethylpiperidine oxide, nitrogen monoxide, diphenyl disulphide, diphenyl diselenide, methanesulphonyl chloride, bromotrichloromethane, or iodine, leads to oxygen- , nitrogen- , sulphur/selenium- or halogen- (34) functionalised products.When these radical-trapping methodologies are combined with cobalt-mediated radical cyclisation reactions (Scheme 2) a powerful synthetic procedure, i.e. radical carbon-to-carbon bond formation with simultaneous functionalisation of the product radical centre, becomes available.
