223677-90-5Relevant articles and documents
Hypophosphite mediated carbon-carbon bond formation: A clean approach to radical methodology
Graham, Stephen R.,Murphy, John A.,Coates, David
, p. 2415 - 2416 (1999)
Hypophosphorous acid (H3PO2) and its corresponding 1-ethylipiperidine salt have been used to mediate carbon-carbon bond forming radical reactions in both aqueous and organic media. The methods used avoid many of the problems associated with tributyltin hydride based methodology.
Synthetic utility of tribenzyltin hydride and its derivatives as easily accessible, removable, and decomposable organotin reagents
Yamakawa, Takeshi,Kinoshita, Hidenori,Miura, Katsukiyo
supporting information, p. 129 - 134 (2013/03/13)
Radical reactions using tribenzyltin hydride (Bn3SnH) easily prepared from tin and benzyl chloride were studied. The Et3B- initiated reduction and cyclization of haloalkanes and haloalkenes with Bn 3SnH proceeded efficiently. Homolytic hydrostannylation of alkynes with Bn3SnH followed by treatment with electrophiles gave functionalized alkenes in good to high yields. The organotin byproducts formed could be easily removable by filtration and silica-gel column chromatography without any pretreatment. It was also found that tribenzyltin chloride (Bn 3SnCl) easily decomposed to benzyl alcohol in a basic solution of H2O2.
Indium-catalyzed radical reductions of organic halides with hydrosilanes
Miura, Katsukiyo,Tomita, Mitsuru,Yamada, Yusuke,Hosomi, Akira
, p. 787 - 792 (2007/10/03)
(Equation Presented) The In(OAc)3-catalyzed reaction of bromo- and iodoalkanes with PhSiH3 in THF at 70°C gave dehalogenated alkanes in good to high yields. In the presence of Et3B and air, the reduction proceeded smoothly at 30°C. When 2,6-lutidine and air were used as additives, the In(OAc)3-catalyzed system enabled an efficient reduction of simple and functionalized iodoalkanes in EtOH. Catalytic use of GaCl3 was found to be effective in the reduction of haloalkanes with poly(methylhydrosiloxane) (PMHS). These catalytic reductions probably involve a radical chain mechanism in which indium or gallium hydride species work as the actual reductants.
Development of radical reactions with zirconocene complexes as electron transfer reagents
Fujita, Kazuya,Yorimitsu, Hideki,Oshima, Koichiro
, p. 1727 - 1736 (2007/10/03)
Bis(cyclopentadienyl)zirconium chloride hydride (Schwartz reagent) proved to be an efficient radical chain carrier for radical reduction of organic halides. Treatment of 1-bromoadamantane with Cp2Zr(H)Cl in THF at 25°C in the presence of triethylborane furnished adamantane quantitatively. Radical cyclization of 2-haloalkyl allyl ethers afforded five-membered products under the same reaction conditions. Reduction with Cp2Zr(H)Cl generated in situ from Cp2ZrCl2 and sodium bis(2-methoxyethoxy)aluminium hydride (Red-Al) also proceeded smoothly. Moreover, the reduction could function by using a catalytic amount of Cp 2ZrCl2. A zirconocene-olefin complex also induced reductive radical cyclization of 2-haloalkyl allyl ethers in THF. This complex served as a single electron transfer reagent to promote the radical cyclization. Furthermore, the cyclization reaction in DME afforded 3- tetrahydrofuranylmethylzirconium efficiently.
Radical reaction by a combination of phosphinic acid and a base in aqueous media
Yorimitsu,Shinokubo,Oshima
, p. 225 - 235 (2007/10/03)
Treatment of various organic halides with phosphinic acid (hypophosphorous acid) in aqueous ethanol in the presence of a radical initiator and a base gave the corresponding reduced products in high yields. Addition of a base is indispensable for the reduction of halides by phosphinic acid. Allylic ether of o-iodophenol or 2-haloalkanal allylic acetal underwent radical cyclization under the same conditions to afford the corresponding cyclic product in excellent yield. Deuterated phosphinic acid was found to be an efficient chain carrier for the radical deuteration of organic halides. For example, a deuterium oxide solution of deuterated phosphinic acid, potassium carbonate, 2,2′-azobis(isobutyramidine) dihydrochloride as an initiator, and p-iodobenzoic acid was heated at reflux to give p-deuteriobenzoic acid in 94% yield. A mixed dioxane/D2O solvent system combined with DBU and potassium peroxodisulfate was crucial to deuterate hydrophobic substrates in high yields and with high deuterium incorporation. Complete deuterium incorporation was accomplished only by the reaction in D2O without an organic cosolvent and an organic base.
Radical cyclization reaction using a combination of phosphinic acid and a base in aqueous ethanol
Yorimitsu, Hideki,Shinokubo, Hiroshi,Oshima, Koichiro
, p. 104 - 105 (2007/10/03)
Treatment of allylic ether of 2-iodophenol or 2-haloethanal allylic acetal with phosphinic acid, a base and a radical initiator (AIBN or triethylborane) in aqueous ethanol provided the corresponding radical cyclization product in excellent yield. An addit
