- Formation of quaternary centers by copper-catalyzed asymmetric conjugate addition of alkylzirconium reagents
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Pure and simple: Alkylzirconocenes generated in situ from simple alkenes are used in highly enantioselective copper-catalyzed 1,4-addition reactions to trisubstituted cyclic enones to generate quaternary centers. These reactions operate at room temperature under a range of conditions and tolerate many functional groups. Cp=cyclopentadienyl, Tf=trifluoromethanesulfonyl. Copyright
- Sidera, Mireia,Roth, Philippe M. C.,Maksymowicz, Rebecca M.,Fletcher, Stephen P.
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supporting information
p. 7995 - 7999
(2013/08/23)
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- The copper mediated Barbier reactions of α,β-unsaturated ketones: Regioselective conjugate and 1,2-addition
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The one-pot reaction of isophorone and other α,β-unsaturated ketones with alkyl and aryl halides in the presence of magnesium and a copper salt ('Barbier' conditions) leads to the regiospecific formation of 1,4-addition products; the use of lithium leads to regioselective 1,2-addition.
- Costello, Declan P.,Geraghty, Niall W. A.
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p. 3083 - 3096
(2007/10/03)
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- The Kharasch reaction revisited: CuX3Li2-catalyzed conjugate addition reactions of Grignard reagents
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The conjugate addition of Grignard reagents RMgX to α,β-unsaturated ketones and esters is effectively catalyzed by soluble copper ate-complexes of the type CuX3Li2, e.g.CuI*2LiCl.In the presence of Me3SiCl the corresponding ketone enolsilanes are formed in high yield and selectivity.Diastereoselectivity in the case of chiral ketones is similar to that observed by using stoichiometric amounts of cuprates R2CuLi.Thus CuX3Li2-catalyzed 1,4-additions of Grignard reagents may be an industrially viable process.Keywords: Copper; Magnesium; Lithium; Silicon; Ketone; Enolsilanes
- Reetz, Manfred T.,Kindler, Alois
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- ORGANOMANGANESE (II) REAGENTS XVI: COPPER-CATALYZED 1,4-ADDITION OF ORGANOMANGANESE CHLORIDES TO CONJUGATED ENONES
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Copper-catalyzed conjugate addition of organomanganese chlorides to conjugated enones in THF, at 0 deg C, leads to the 1,4-addition products in high yields.The scope of the reaction is very large and the results are generally better than those obtained from organomagnesium compounds in the presence of a copper salts as well as from organocopper or cuprate reagents.Furthermore organomanganese chlorides are indisputably cheaper and more stable than the latter.
- Cahiez, Gerard,Alami, Mouad
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p. 3541 - 3544
(2007/10/02)
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- CHLOROSILANE-ACCELERATED CONJUGATE ADDITION OF CATALYTIC AND STOICHIOMETRIC ORGANOCOPPER REAGENTS
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Trialkylsilyl chlorides, particularly in combination with hexamethylphosphoramide or 4-dimethylaminopyridine, dramatically accelerates the conjugate addition of catalytic and stoichiometric organocopper reagents onto enones, enals, and enoates, in which very high degrees of stereo- and chemoselectivities were observed.
- Matsuzawa, Satoshi,Horiguchi, Yoshiaki,Nakamura, Eiichi,Kuwajima, Isao
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p. 349 - 362
(2007/10/02)
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- Synthesis and Reactivity toward Acyl Chlorides and Enones of the New Highly Functionalized Copper Reagents RCu(CN)ZnI
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The new and highly functionalized copper reagents RCu(CN)ZnI obtained from readily available primary and secondary alkylzinc iodides by a transmetalation in THF with the soluble salt, CuCN*2LiX, react in good yields with acyl chlorides and enones, respectively, to afford ketones and 1,4-addition products.
- Knochel, Paul,Yeh, Ming Chang P.,Berk, Scott C.,Talbert Jason
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p. 2390 - 2392
(2007/10/02)
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