proved also useful as a catalyst in numerous organic reactions. Commercial availability and lower cost than precious metalcomplexes, make cobalamin an attractive candidate for a broader use as a benign Co-catalyst. Herein, the vitamin B12-catalyzed dicarbofuntionalization of bromoalkenes with electrophilic olefins is reported leading to substituted pyrrolidines and piperidines in decent yields after only
Cobalt-catalyzed cross-coupling reactions of alkyl halides with aryl Grignard reagents and their application to sequential radical cyclization/cross-coupling reactions
Reactions of alkyl halides with arylmagnesium bromides in the presence of cobalt(II)(diphosphine) complexes are discussed. Treatment of 1-bromooctane with phenylmagnesium bromide with the aid of a catalytic amount of CoCl2(dppp) [DPPP=1,3-bis(diphenylphosphino)propane] yielded octylbenzene in good yield. The reaction mechanism would include single electron transfer from an electron-rich cobalt complex
Single-Electron-Transfer Strategy for Reductive Radical Cyclization: Fe(CO)<sub>5</sub> and Phenanthroline System
作者:Joon Young Hwang、Jong Hwa Baek、Tae Il Shin、Jung Ha Shin、Jae Won Oh、Kwang Pyo Kim、Youngmin You、Eun Joo Kang
DOI:10.1021/acs.orglett.6b02375
日期:2016.10.7
electron-transfer strategy using low-valent iron pentacarbonyl [Fe(CO)5] to generate radical species from alkyl iodides was achieved. A range of pyrrolidines, tetrahydrofurans, and carbocycles were synthesized via 5-exo cyclization reactions of alkyl radical intermediates generated by electron transfer from a system involving Fe(CO)5, 1,10-phenanthroline, and diisopropylamine. Moreover, tandem addition
Synthesis of Cp*CH2PPh2 and its use as a ligand for the nickel-catalysed cross-coupling reaction of alkyl halides with aryl Grignard reagents
作者:Minoru Uemura、Hideki Yorimitsu、Koichiro Oshima
DOI:10.1039/b612173j
日期:——
A new ligand, Cp*CH2PPh2 (Cp* = 1,2,3,4,5-pentamethyl-2,4-cyclopentadienyl), was prepared, and was used as a ligand for nickel-catalysed cross-couplingreaction of alkylhalides with aryl Grignard reagents, which nickel-phosphine complexes had never made possible.
Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
作者:J. Johan Verendel、Jia-Qi Li、Xu Quan、Byron Peters、Taigang Zhou、Odd R. Gautun、Thavendran Govender、Pher G. Andersson
DOI:10.1002/chem.201104073
日期:2012.5.21
Several types of chiral hetero‐ and carbocycliccompounds have been synthesized by using the asymmetrichydrogenation of cyclicalkenes. N,P‐Ligated iridium catalysts reduced six‐membered cyclicalkenes with various substituents and heterofunctionality in good to excellent enantioselectivity, whereas the reduction of five‐membered cyclicalkenes was generally less selective, giving modest enantiomeric