167029-87-0Relevant academic research and scientific papers
Radical reductions of alkyl halides bearing electron withdrawing groups with N-heterocyclic carbene boranes
Ueng, Shau-Hua,Fensterbank, Louis,Lacote, Emmanuel,Malacria, Max,Curran, Dennis P.
supporting information; experimental part, p. 3415 - 3420 (2011/06/25)
1,3-Dimethylimidazol-2-ylidene borane and 2,4-dimethyl-1,2,4-triazol-3- ylidene borane are found to be useful reagents for the reduction of alkyl iodides and bromides bearing nearby electron withdrawing substituents. Signatures of radical chain reactions are seen in many cases, but ionic reductions may also be occurring with some substrates. The reagents are attractive because of their low molecular weight, their availability from inexpensive precursors, and their stability. Separation of the borane products from the target products is readily accomplished either with or without prior regeneration of the borane for later reuse. 2,4-Dimethyl-1,2,4-triazol-3-ylidene borane is versatile because both starting borane and its derived products can be removed by extraction with water.
Atom transfer radical cyclisations of activated and unactivated N-allylhaloacetamides and N-homoallylhaloacetamides using chiral and non-chiral copper complexes
Clark, Andrew J.,De Campo, Floryan,Deeth, Robert J.,Filik, Robert P.,Gatard, Sylvain,Hunt, Nicola A.,Lastecoueres, Dominique,Thomas, Gerard H.,Verlhac, Jean-Baptiste,Wongtap, Hathaichanuk
, p. 671 - 680 (2007/10/03)
Activated N-tosyl-2,2,2-trichloroacetamide 6a, N-benzyl-2,2,2-trichloroacetamide 6d, 2,2-dichloroacetamides 6b-c and 6e-f and 2-monohaloacetamides lla-g undergo efficient 5-exo atom transfer radical cyclisations at room temperature mediated by CuCl or CuBr in the presence of tris(N,N-dimethylaminoethylene)amine 3 (trien-Me6). The efficiency and stereoselectivity of these cyclisations was found to be greater than existing published atom transfer procedures based upon CuCl(bipyridine), RuCl2(PPh3)3 and CuCl(TMEDA)2. The product distribution for the cyclisation onto alkyne 11g was found to be solvent dependent. Attempts to make larger ring sizes by endo cyclisation of N-tosylacetamides 19a-c led to a competing 5-exo ipso aromatic substitution into the N-tosyl group followed by re-aromatisation and loss of SO2 to furnish an amidyl radical. Cyclisation of N-homoallylacetamides 25a-d proceeded smoothly to give δ-lactams with a range of catalysts based upon ligands 2 and 26. The stereoselectivity of cyclisation to give γ lactams could be somewhat influenced by using chiral enantiopure copper complexes 28-30 suggesting that the reactions may involve metal-complexed radicals.
Indirect electroreductive cyclization of N-allyl and N-propargylamides using a nickel(II) complex as an electron-transfer catalyst: Selective formation of halogenated and non-halogenated pyrrolidinones
Ozaki,Matsushita,Emoto,Ohmori
, p. 32 - 36 (2007/10/02)
Nickel(II) complex-catalyzed indirect electroreduction of N-allyl and N-propargyl-α-bromoamides conducted in dimethylformamide with 2 eq of a hydrogen atom donor, diphenylphosphine, afforded the corresponding pyrrolidinones as the sole cyclized product in
