- Synthesis of Allenes by Catalytic Coupling of Propargyl Carbonates with Aryl Iodides in the Presence of Diboron Species
-
Bimetallic copper-/palladium-catalyzed multicomponent reaction of propargyl carbonates, aryl iodides, and diboron species was studied. This procedure can be used for synthesis of di-, tri-, and tetra-substituted allenes. Using diboronic acid, the reaction
- Yang, Yuzhu,Szabó, Kálmán J.
-
p. 250 - 255
(2016/01/15)
-
- Gold(I)-catalyzed rearrangement of propargyl benzyl ethers: A practical method for the generation and in situ transformation of substituted allenes
-
A series of benzyl propargyl ethers react with a gold(I) catalyst to furnish variously substituted allenes via a 1,5-hydride shift/fragmentation sequence. This transformation is rapid and practical. It can be performed under very mild conditions (room temperature or 60 °C) using terminal as well as substituted alkyne substrates bearing a primary, secondary, or tertiary benzyl ether group. The allenes thus formed can be reacted in situ with an internal or external nucleophile, corresponding to an overall reductive substitution process, to produce more functionalized compounds.
- Bolte, Benoit,Odabachian, Yann,Gagosz, Fabien
-
supporting information; experimental part
p. 7294 - 7296
(2010/08/05)
-
- Stereoselective synthesis of chiral 3-aryl-1-alkynes from bromoallenes and heterocuprates
-
The synthesis of chiral 3-aryl-1-alkynes 3 via cross-coupling of 3-alkyl- and 3,3-dialkyl-1-bromo-1,2-dienes 1 and arylbromocuprates (RCuBr)MgBr-LiBr 2 was examined. With phenylcopper reagents and its para-substituted derivatives, as well as with 2-naphth
- Caporusso, Anna Maria,Zampieri, Alessia,Aronica, Laura Antonella,Banti, Donatella
-
p. 1902 - 1910
(2007/10/03)
-
- Synthesis of allenes by double Horner-Wadsworth-Emmons reaction
-
LDA treatment of aldehydes or ketone with alkenylphosphonates 2, prepared by Horner-Wadsworth-Emmons (HWE) reaction of methylenebisphosphonate 1 with aldehydes, afforded Baylis-Hillman reaction-type products 5 in high yields. HWE olefination of 5 with KH or KH-18-crown-6 as a base provided allenes in good yields. One-flask procedure was successfully developed starting from 1 to afford an allene in a reasonably good yield.
- Inoue, Hideki,Tsubouchi, Hiroshi,Nagaoka, Yasuo,Tomioka, Kiyoshi
-
-
- Coupling of chiral 1-bromo-1,2-dienes with zinc-based cuprates: A new procedure for the regio and stereoselective synthesis of functionalized acetylenic compounds
-
Zinc alkylcyanocuprates (Knochel reagents) are found to be active in the cross-coupling reaction with allenic bromides affording acetylenic products with a high regio and stereoselective 1,3-anti substitution. The coupling process, which has been successf
- Caporusso, Anna Maria,Filippi, Sara,Barontini, Federica,Salvadori, Piero
-
p. 1227 - 1230
(2007/10/03)
-
- Direct Determination of the Enantiomeric Purity of Chiral Trisubstituted Allenes by Using Permethylated Cyclodextrin as a Chiral Solvating Agent
-
The heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TRIMEB) has been successfully used as convenient chiral solvating agent to determine the enantiomeric composition of chiral trisubstituted allenes by 1H NMR spectroscopy: the analysis of the effect of the molar ration TRIMEB/allene, temperature, and nature of the solvent allowed us to optimize the experimental conditions to enhance the separation between the signals of the two enantiomers of each allene.
- Uccello-Barretta, Gloria,Balzano, Federica,Caporusso, Anna Maria,Salvadori, Piero
-
p. 836 - 839
(2007/10/02)
-
- REACTIONS OF 3-ALKYL- AND 3,3-DIALKYL-1-BROMOALLENES WITH ORGANOCUPRATES: EFFECTS OF THE NATURE OF THE CUPRATE REAGENT ON THE REGIO- AND STEREOSELECTIVITY
-
Organocuprates induce 1,3- and direct substitution in 3-alkyl- and 3,3-dialkyl-1-bromo-1,2-dienes leading respectively to either terminal acetylenes or allenic hydrocarbons.The nature of the cuprate exerts a prominent role in determining both the regio- and the stereochemistry of these reactions.
- Caporusso, Anna Maria,Polizzi, Carmela,Lardicci, Luciano
-
p. 6073 - 6076
(2007/10/02)
-
- Palladium-Catalyzed Propargylic vs. Allylic Alkylation
-
The relative reactivities of allylic propargylic acetates toward palladium(0)-catalyzed substitution by various nucleophiles were studied bu using three types of model substrates: (a) monofunctional allylic and propargylic acetates with similar structural properties; (b) a bifunctional substrate containing both allyl and propargyl functionalities with no apparent interaction between them; (c) conjugated bifunctional systems, in which the two functionalities may interact with one another.Palladium(0)-catalyzed substitution of propargylic acetates by various carbon nucleophiles was found to be less general than the analogous substitution of allylic acetates.Three modes of reactivity were observed, corresponding to three groups of nucleophiles; (a) stabilized carboanions such as sodium dimethyl malonate, which do not react with propargylic acetates but react readily with allylic acetates; (b) nonstabilized organometallics such as phenylzinc chloride, which react with propargylic and allylic acetates at comparable rates (reaction with the former yielding the allenic product exlusively); and (c) allyl- and allenylstannanes, which react with allylic acetates but do not react with isolated propargylic acetates (except for special cases where the propargylic acetate is also an allylic one).Certain similarities between regioselectivity phenomena in organopalladium and organocopper chemistry are discussed.
- Keinan, Ehud,Bosch, Eric
-
p. 4006 - 4016
(2007/10/02)
-
- METAL CATALYSIS IN ORGANIC REACTIONS. 17. A NICKEL-PROMOTED ROUTE TO SUBSTITUTED ALLENES BY REACTION OF 1-BROMO-1,2-DIENES WITH ALKYL METALS.
-
Nickel complexes are found to be catalytically active in the cross-coupling reactions of allenic bromides with alkyl metals to give substituted allenes in excellent yields.The catalytic process proceeds generally with inversion of configuration in the allenyl moiety.
- Caporusso, Anna Maria,Settimo, Federico Da,Lardicci, Luciano
-
p. 5101 - 5104
(2007/10/02)
-