Electrochemical allylation of aldehydes in a solvent-free cavity cell with a graphite powder cathode
Mixtures of carbonyl compounds and allyl halides, adsorbed on a graphite powder cathode, were reduced under aqueous anolyte to give high yields of homoallylic alcohols. Catalytic amounts of silver or tetrabutylammonium tetrafluoroborate improved the yields significantly. Inexpensive allyl chloride gave superior results when compared to allyl bromide.
De Souza, Ronny F. M.,Areias, Madalena C. C.,Bieber, Lothar W.,Navarro, Marcelo
A Mechanochemical Zinc-Mediated Barbier-Type Allylation Reaction under Ball-Milling Conditions
A ball-milling-enabled zinc-mediated Barbier-type allylation reaction is reported. Notably, running the reaction in this manner renders it effective irrespective of the initial morphology of the zinc metal. The process is operationally simple, does not re
Yin, JieXiang,Stark, Roderick T.,Fallis, Ian A.,Browne, Duncan L.
p. 2347 - 2354
(2020/02/04)
Anti-Markovnikov Hydrofunctionalization of Alkenes: Use of a Benzyl Group as a Traceless Redox-Active Hydrogen Donor
A protocol for the anti-Markovnikov hydrofunctionalization of alkenes has been developed by the use of a benzyl group as a traceless redox-active hydrogen donor. Under copper catalysis and in the presence of CF3- or N3-containing hyp
α-Trifluoromethylated tertiary homoallylic amines: Diastereoselective synthesis and conversion into β-aminoesters, γ- And δ-aminoalcohols, azetidines and pyrrolidines
The diastereoselective addition of allyl zinc and allylindium derivatives to α-trifluoromethyl N-tert-butanesulfinyl hemiaminals, bench stable precursors of aryl and alkyl trifluoromethyl ketimines, allows the synthesis of homoallylic amines containing a tetrasubstituted carbon stereocentre bearing a trifluoromethyl group with good diastereoselectivities (up to dr > 99:1). This approach was also suitable for accessing chiral homoallylic amines bearing two contiguous stereocenters. The synthetic usefulness of N-tert-butanesulfinyl homoallylamines was illustrated by preparing various trifluoromethylated nitrogen containing bifunctional synthons (aminoesters, aminoalcohols) and small azaheterocycles (azetidines, pyrrolidines).
Catalytic enantioselective addition of organoboron reagents to fluoroketones controlled by electrostatic interactions
Organofluorine compounds are central to modern chemistry, and broadly applicable transformations that generate them efficiently and enantioselectively are in much demand. Here we introduce efficient catalytic methods for the addition of allyl and allenyl organoboron reagents to fluorine-substituted ketones. These reactions are facilitated by readily and inexpensively available catalysts and deliver versatile and otherwise difficult-to-access tertiary homoallylic alcohols in up to 98% yield and >99:1 enantiomeric ratio. Utility is highlighted by a concise enantioselective approach to the synthesis of the antiparasitic drug fluralaner (Bravecto, presently sold as the racemate). Different forms of ammonium-organofluorine interactions play a key role in the control of enantioselectivity. The greater understanding of various non-bonding interactions afforded by these studies should facilitate the future development of transformations that involve fluoroorganic entities.
Lee, Kyunga,Silverio, Daniel L.,Torker, Sebastian,Robbins, Daniel W.,Haeffner, Fredrik,Van Der Mei, Farid W.,Hoveyda, Amir H.
p. 768 - 777
(2016/07/29)
Efficient allylation of active ketones promoted by p-nitrobenzoic acid
A general and practical method of allylation of carbonyl compounds promoted by p-nitrobenzoic acid under mild reaction condition has been developed. p-Nitrobenzoic acid can be easily recovered after workup by aqueous HCl.
Xie, Zhengfeng,Li, Guilong,Zhao, Gang,Wang, Jide
experimental part
p. 1212 - 1216
(2010/11/16)
Mise en evidence d'une reactivite specifique des trifluoromethylcetones vis-a-vis du bromure d'allylmagnesium
We wish to report on an unusual reactivity of allylmagnesium bromide.This Grignard reagent acts as a reducing agent towards trifluoromethylated ketones.A single electron transfer is suggested to explain the reductive process.By using an excess of allylmagnesium bromide, an exclusive addition reaction is obtained.The stereochemistry of both addition and reduction reactions is discussed. - Keywords: Trifluoromethyl ketones; Trifluoromethyl alcohols; Allylmagnesium bromide; Single electron transfer; Stereochemistry; NMR spectroscopy; IR spectroscopy; Mass spectrometry
Felix, Caroline,Laurent, Andre,Mison, Pierre
p. 71 - 82
(2007/10/02)
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