2248-23-9Relevant academic research and scientific papers
Expanding Mg-Zn hybrid chemistry: Inorganic salt effects in addition reactions of organozinc reagents to trifluoroacetophenone and the implications for a synergistic lithium-magnesium-zinc activation
Armstrong, David R.,Clegg, William,Garcia-Ulvarez, Pablo,Kennedy, Alan R.,McCall, Matthew D.,Russo, Luca,Hevia, Eva
, p. 8333 - 8341 (2011)
Numerous organic transformations rely on organozinc compounds made through salt-metathesis (exchange) reactions from organolithium or Grignard reagents with a suitable zinc precursor. By combining X-ray crystallography, NMR spectroscopy and DFT calculations, this study sheds new light on the constitution of the organometallic species involved in this important synthetic tool. Investigations into the metathesis reactions of equimolar amounts of Grignard reagents (RMgX) and ZnCl2 in THF led to the isolation of novel magnesium-zinc hybrids, [{(thf)2Mg(μ-Cl)3ZnR} 2] (R=Et, tBu, nBu or o-OMe-C6H4), which exhibit an unprecedented structural motif in mixed magnesium-zinc chemistry. Furthermore, theoretical modelling of the reaction of EtMgCl with ZnCl 2 reveals that formation of the mixed-metal compound is thermodynamically preferred to that of the expected homometallic products, RZnCl and MgCl2. This study also assesses the alkylating ability of hybrid 3 towards the sensitive ketone trifluoroacetophenone, revealing a dramatic increase in the chemoselectivity of the reaction when LiCl is introduced as an additive. This observation, combined with recent related breakthroughs in synthesis, points towards the existence of a trilateral Li/Mg/Zn synergistic effect. Copyright
Catalytic asymmetric β-hydrogen transfer reduction of α-trifluoromethyl aromatic ketones with diethylzinc
Huang, Huayin,Zong, Hua,Bian, Guangling,Song, Ling
, p. 835 - 839 (2015/08/18)
Abstract The catalytic asymmetric β-hydrogen transfer reduction of α-trifluoromethyl ketones using diethylzinc as the β-hydrogen donor was developed with the use of phosphinamide chiral ligand. The corresponding alcohol products were afforded in good yields with up to 73% ee. This method was successfully applied to the chemo- and enantioselective reduction of α-methyl/trifluoromethyl diketone, affording 88% yield and 70% ee of the fluorinated hydroxylketone product.
Catalytic enantioselective addition of diethylzinc to trifluoromethyl ketones
Yearick, Kimberly,Wolf, Christian
supporting information; scheme or table, p. 3915 - 3918 (2009/05/31)
(Figure Presented) A procedure for nucleophilic addition of diethylzinc to trifluoramethyl ketones was developed. The TMEDA-catalyzed method converts aromatic substrates to the corresponding 2-aryl-1,1,1-trifluorobutan-2-ols in up to 99% yield, and it is also applicable to less reactive aliphatic ketones if stoichiometric ligand amounts are employed. The first asymmetric variant producing tertiary alcohols with up to 61% ee when TBOX is used as catalyst is described.
Nucleophilic trifluoromethylation of carbonyl compounds and disulfides with trifluoromethane and silicon-containing bases
Large,Roques,Langlois
, p. 8848 - 8856 (2007/10/03)
Provided that DMF (or another N,N-dialkylformamide) is present in the reaction medium, at least in a catalytic amount, fluoroform trifluoromethylates efficiently carbonyl compounds, even enolizable ones, when opposed to (TMS)2N- M+, generated in situ from N(TMS)3 and M+ F- or RO- Na+. When F- is used in a catalytic amount, silylated α-(trifluoromethyl)carbinols are obtained: In this case, the four-component system HCF3/N(TMS)3/catalytic F-/catalytic DMF behaves like the Ruppert's reagent, especially as far as nonenolizable carbonyl compounds are concerned (CF3SiMe3 remains more efficient for enolizable carbonyl compounds). This process involves an adduct between DMF and -CF3 which is the true trifluoromethylating agent. In the same way, fluoroform efficiently trifluoromethylates disulfides and diselenides when deprotonated with a strong base selected from t-BuOK or N(SiMe3)3/Me4NF (or TBAT). t-BuOK is more adapted to the trifluoromethylation of awl disulfides whereas N(SiMe3)3/F- is Well suited to that of aliphatic disulfides.
