15232-85-6Relevant articles and documents
Terminal-Selective Functionalization of Alkyl Chains by Regioconvergent Cross-Coupling
Dupuy, Stéphanie,Zhang, Ke-Feng,Goutierre, Anne-Sophie,Baudoin, Olivier
, p. 14793 - 14797 (2016/11/23)
Hydrocarbons are still the most important precursors of functionalized organic molecules, which has stirred interest in the discovery of new C?H bond functionalization methods. We describe herein a new step-economical approach that enables C?C bonds to be constructed at the terminal position of linear alkanes. First, we show that secondary alkyl bromides can undergo in situ conversion into alkyl zinc bromides and regioconvergent Negishi coupling with aryl or alkenyl triflates. The use of a suitable phosphine ligand favoring Pd migration enabled the selective formation of the linear cross-coupling product. Subsequently, mixtures of secondary alkyl bromides were prepared from linear alkanes by standard bromination, and regioconvergent cross-coupling then provided access to the corresponding linear arylation product in only two steps.
β- and γ-disubstituted olefins: Substrates for copper-catalyzed asymmetric allylic substitution
Falciola, Caroline A.,Tissot-Croset, Karine,Reyneri, Hugo,Alexakis, Alexandre
supporting information; scheme or table, p. 1090 - 1100 (2009/05/30)
The copper-catalyzed asymmetric allylic alkylation has shown through many examples that it is a powerful means to generate stereogenic centers with mono β- and γ-substituted olefinic substrates. However, little has been reported about more substituted olefinic patterns, such as β-disubstituted allylic electrophiles. In this paper, we show that a simple procedure using easily accessible Grignard reagents and as low as 3 mol% of copper/ligand can promote high to nearly perfect enantioselectivities (up to >99% ee) with very good γ-selectivities on a wide panel of aliphatic or aromatic β-disubstituted substrates.
β-disubstituted allylic chlorides: Substrates for the Cu-catalyzed asymmetric SN2′ reaction
Falciola, Caroline A.,Tissot-Croset, Karine,Alexakis, Alexandre
, p. 5995 - 5998 (2007/10/03)
Scope broadened: A previously developed asymmetric Cu-catalyzed allylic substitution can be applied to more substituted allylic patterns. Two classes of β-disubstituted substrates, cinnamyl derivatives and aliphatic endocyclic allylic chlorides, afford excellent regio- and enantioselectivities (see schemes; L* = phosphoramidite ligand). (Chemical Equation Presented).
New efficient nickel- and palladium-catalyzed cross-coupling reactions mediated by tetrabutylammonium iodide
Piber, Michael,Jensen, Anne Eeg,Rottlaender, Mario,Knochel, Paul
, p. 1323 - 1326 (2008/02/09)
(formula presented) The addition of Bu4NI has been found to accelerate the palladium(0)-catalyzed cross-coupling between benzylic zinc bromides and aryl or alkenyl triflates. Remarkably, it further allows a new nickel(0)-catalyzed cross-coupling between functionalized benzylic zinc reagents and primary alkyl iodides leading to polyfunctional products in good yields under mild reaction conditions (0-20 °C, 4-16 h).
p-Toluenesulfonic Acid Adsorbed on Silica Gel: An Efficient Dehydrating Agent of Alcohols
D'Onofrio, Franco,Scettri, Arrigo
, p. 1159 - 1161 (2007/10/02)
Secondary and tertiary alcohols are efficiently dehydrated by reaction with p-toluenesulfonic acid supported on silica gel.In particular, the procedure allows the direct conversion of 3-hydroxy-steroids into Δ2-olefins or Δ3,5-dienes, without passing through the mesylate or tosylate esters.
