1242106-24-6Relevant articles and documents
Asymmetric addition of cyanide to β-nitroalkenes catalysed by chiral salen complexes of Titanium(IV) and Vanadium(V)
North, Michael,Watson, James M.
, p. 2405 - 2409 (2013)
Structurally well-defined bimetallic titanium(IV) (salen) and monometallic vanadium(V) (salen) complexes have been used as catalysts for the asymmetric addition of trimethylsilyl cyanide to β-nitroalkenes to produce chiral nitronitriles with ee values in the range of 79-89% and conversions up to 100% at 0°C. The reaction conditions (solvent, temperature, time and vanadium complex counter-ion) were optimised, and it was shown that the catalyst loading could be significantly reduced (20 to 2mol%) and the reaction temperature increased (-40 to 0°C) compared to previous studies that used an insitu prepared catalyst. The results are compared and contrasted with previous results obtained by using the same catalysts for the asymmetric addition of trimethylsilyl cyanide to aldehydes, and a transition-state structure for the asymmetric addition of trimethylsilyl cyanide to nitroalkenes is proposed to account for the observed stereochemistry.
Asymmetric hydrocyanation of nitroolefins catalyzed by an aluminum(iii) salen complex
Jakhar, Ajay,Sadhukhan, Arghya,Khan, Noor-Ul H.,Saravanan,Kureshy, Rukhsana I.,Abdi, Sayed H. R.,Bajaj, Hari C.
, p. 2656 - 2661 (2014)
Chiral AlIII salen complexes were synthesized and used as catalysts for the asymmetric hydrocyanation of nitroolefins using 4-phenylpyridine N-oxide as an additive and trimethylsilyl cyanide (TMSCN) as a source of cyanide. An excellent yield of β-nitronitrile (87%) and enantioselectivity (90%) were achieved if (2-nitrovinyl)cyclohexane was used as a substrate at -15C in 16h. To understand the interaction of the AlIII salen complex and additive, NMR and IR spectroscopic studies revealed that 4-phenylpyridine N-oxide acts both as an axial ligand and helps to activate the cyanide source TMSCN, which thereby increases the reactivity. A catalytic cycle was proposed based on the spectroscopic studies.
Synthesis of enantioenriched azo compounds: Organocatalytic Michael addition of formaldehyde N-tert-butyl hydrazone to nitroalkenes
Monge, David,Daza, Silvia,Bernal, Pablo,Fernandez, Rosario,Lassaletta, Jose M.
, p. 326 - 335 (2013/02/23)
The unprecedented diaza-ene reaction of formaldehyde N-tert-butyl hydrazone with nitroalkenes can be efficiently catalyzed by an axially chiral bis-thiourea to afford the corresponding diazenes in good to excellent yields (60-96%) and moderate enantiosele
Asymmetric cyanation of nitroalkenes catalyzed by a salen-titanium catalyst
Lin, Li,Yin, Wen,Fu, Xu,Zhang, Jinlong,Ma, Xiaojuan,Wang, Rui
experimental part, p. 83 - 89 (2012/01/14)
The salen-Ti complex catalyzed cyanation of nitroolefins was accomplished via the silyl nitronate intermediate for the synthesis of chiral β-nitronitriles with e.r. up to 92:8 and high yields (up to 90%). The catalyst also kept a high turnover frequency a
Organocatalytic asymmetric cyanosilylation of nitroalkenes
Bernal, Pablo,Fernandez, Rosario,Lassaletta, Jose M.
supporting information; experimental part, p. 7714 - 7718 (2010/09/10)
(Figure Presented) New catalyst, new reaction: The unprecedented cyanosilylation of nitroalkenes can be efficiently catalyzed by a bifunctional quinine derivative with tetraalkylammonium cyanide and thiourea moieties. The activation of the nitroalkene by hydrogen bonding to the thiourea, together with the presence of an active cyanide, provides new mode of activation that leads to products in high yields and good selec tivities (see scheme).
