50559-00-7Relevant academic research and scientific papers
Electrochemical reduction of 1-bromomethyl-2-oxocycloalkane-1-carboxylates at silver cathodes in dimethylformamide: One-carbon ring-expansion reactions
Wappes, Ethan A.,Mubarak, Mohammad S.,Peters, Dennis G.
, p. G122 - G127 (2015/04/14)
Cyclic voltammetry and controlled-potential (bulk) electrolysis have been employed to investigate the separate electrochemical reductions of methyl 1-bromomethyl-2-oxocyclopentane-1-carboxylate (1) and ethyl 1-bromomethyl-2-oxocyclohexane-1-carboxylate (2) at silver cathodes in dimethylformamide (DMF) containing 0.10 M tetramethylammonium tetrafluoroborate (TMABF4). Oneelectron reductive cleavage of the carbon-bromine bond of each substrate yields a radical intermediate that undergoes a ring-expansion reaction, followed by hydrogen-atom abstraction from the solvent, to afford methyl 3-oxocyclohexane-1-carboxylate (3a) and ethyl 3-oxocycloheptane-1-carboxylate (3b), respectively, in good yield. Each substrate gives rise to three other products: (a) a debrominated analogue of each starting material, (b) a dimeric species formed via radical coupling, and (c) a species possessing an ester group extended by one carbon atom. Electrolyses of 1 and 2 done in the presence of D2O have revealed that carbanion intermediates result in small amounts from two-electron cleavage of carbon-bromine bonds. A mechanistic scheme, involving both radicals and carbanions, is proposed to account for the formation of the various products.
Environmentally friendly TPDS-mediated free radical ring expansion of α-haloalkyl cyclic β-keto esters
Sugi, Masaaki,Togo, Hideo
, p. 3171 - 3175 (2007/10/03)
Reactivities of tetraphenyldisilane (TPDS), tris(trimethylsilyl)silane, and tributyltin hydride in the radical ring expansion of α-haloalkyl cyclic β-keto esters were examined. Among these reagents, TPDS was found most effective for the preparation of medium-sized cyclic compounds in terms of yields and ring-expansion/reduction selectivity.
Reductive transformation of α β-epoxy ketones and other compounds promoted through photoinduced electron transfer processes with 1,3-dimethyl- 2-phenylbenzimidazoline (DMPBI)
Hasegawa, Eietsu,Yoneoka, Akira,Suzuki, Kumiko,Kato, Teru,Kitazume, Takashi,Yanagi, Kazuhiro
, p. 12957 - 12968 (2007/10/03)
Photoreactions of epoxy ketones, aromatic ketones, haloketones, and aromatic halides with 1,3-dimethyl-2-phenylbenzimidazoline (DMPBI) were studied. Photoinduced single-electron transfer from DMPBI to such substrates initiates the reactions, followed by radical rearrangement and reduction to finally give several reduced products in modest to good yields.
NOVEL FREE RADICAL RING-EXPANSION REACTIONS
Dowd, Paul,Choi, Soo-Chang
, p. 77 - 90 (2007/10/02)
A novel free radical initiated ring expansion of haloalkyl β-keto esters is described.Following alkylation of the β-keto ester with the appropriate dihalide, the resulting halide is treated at reflux with tri-n-butyltin hydride.Rearrangement to the homolo
