- BIS(ALK-4-ENYL)ZINK-VERBINDUNGEN DURCH ADDITION VON ALK-2-ENYLZINK AN OLEFINE
-
The dialk-2-enylzinc compounds I-IV add to ethylene, oct-1-ene and 3,3-dimethylcyclopropene to give the corresponding di-alk-4-enylzinc compounds VI-IX (88-98percent yield), XV and XVI (90-94percent yield), XVII (7percent) and XXIIIa-XXVIa (91-98percent yield).Additions to XIII are regioselective with Zn -> C(1) while stereoselective cis-addition to XXII is observed.
- Lehmkuhl, Herbert,Doering, Ingo,Nehl, Hans
-
-
Read Online
- Cu-Catalyzed cascades to carbocycles: Union of diaryliodonium salts with alkenes or alkynes exploiting remote carbocations
-
Copper-catalyzed cascade reactions between alkenes or alkynes and diaryliodonium salts form carbocyclic products in a single step. Arylation of the unsaturated functional group is proposed to form a carbocation intermediate that facilitates hydride shift pathways to translocate the positive charge to a remote position and enables ring formation via a Friedel-Crafts-type reaction.
- Zhang, Fengzhi,Das, Shoubhik,Walkinshaw, Andrew J.,Casitas, Alicia,Taylor, Michael,Suero, Marcos G.,Gaunt, Matthew J.
-
supporting information
p. 8851 - 8854
(2014/07/08)
-
- Copper-catalyzed coupling reaction of unactivated secondary alkyl iodides with alkyl Grignard reagents in the presence of 1,3-butadiene as an effective additive
-
Cu-catalyzed cross-coupling of unactivated secondary alkyl iodides with alkyl Grignard reagents in the presence of 1,3-butadiene as a ligand precursor was developed. The use of 1,3-butadiene resulted in improved yields of alkyl-alkyl products with improved selectivities.
- Shen, Ruwei,Iwasaki, Takanori,Terao, Jun,Kambe, Nobuaki
-
supporting information; experimental part
p. 9313 - 9315
(2012/09/21)
-
- Copper-catalyzed allylation of alkyl halides with allylic grignard reagents
-
Treatment of alkyl halides, including secondary and tertiary alkyl bromides, with allylic Grignard reagents in the presence of a catalytic amount of copper(II) triflate in diisopropyl ether at 25 °C yielded the corresponding allylated products in high yie
- Sai, Masahiro,Yorimitsu, Hideki,Oshima, Koichiro
-
experimental part
p. 1194 - 1196
(2009/12/25)
-
- Silver-catalyzed benzylation and allylation reactions of tertiary and secondary alkyl halides with grignard reagents
-
Treatment of alkyl halides, including tertiary alkyl bromides, with benzylic or allylic Grignard reagent in the presence of a catalytic amount of silver nitrate in ether yielded the corresponding cross-coupling products in high yields. The coupling reactions of tertiary alkyl halides provide efficient access to quaternary carbon centers.
- Someya, Hidenori,Ohmiya, Hirohisa,Yorimitsu, Hideki,Oshima, Koichiro
-
scheme or table
p. 969 - 971
(2009/04/10)
-
- All-catalytic, efficient, and asymmetric synthesis of α,ω- diheterofunctional reduced polypropionates via "one-pot" Zr-catalyzed asymmetric carboalumination - Pd-catalyzed cross-coupling tandem process
-
A highly efficient method for the synthesis of stereochemically pure (≥99% ee and >50/1 dr) α,ω-diheterofunctional reduced polypropionates has been developed. The essential features of the method are represented by the conversion of inexpensive styrene in
- Novak, Tibor,Tan, Ze,Liang, Bo,Negishi, Ei-Ichi
-
p. 2838 - 2839
(2007/10/03)
-
- Utilization of tetrabutylammonium triphenyldifluorosilicate as a fluoride source for silicon-carbon bond cleavage
-
Tetrabutylammonium triphenyldifluorosilicate (TBAT) can be employed as a fluoride source to cleave silicon-carbon bonds thus generating in situ carbanions that coupled with a variety of electrophiles, including aldehydes and ketones, in moderate to high yields. Among the examples reported is the first instance of fluoride-induced intermolecular coupling between allyltrimethylsilane and imine derivatives. Also, of particular note is the TBAT-initiated coupling of primary alkyl halides with allyltrimethylsilane. TBAT is an easily handled crystalline solid that has several advantages over tetrabutylammonium fluoride (TBAF) as a fluoride source; it is anhydrous, nonhygroscopic, soluble in most commonly used organic solvents, and less basic than TBAF.
- Pilcher, Anthony S.,DeShong, Philip
-
p. 6901 - 6905
(2007/10/03)
-
- REACTIONS OF STOICHIOMETRIC HIGHER ORDER, MIXED LITHIO MAGNESIO ORGANOCUPRATES
-
Novel higher order cuprates, R(2-thienyl)Cu(CN)LiMgBr (2), are prepared from the 1:1:1 combination of CuCN, 2-lithiothiophene and RMgX.Reactions of various members of this new class of reagents are described, including substitution and conjugate addition processes, where the ligand derived from the Grignard reagent is selectively transferred.The effects of added BF3*Et2O are discussed.Some comparison reactions with the corresponding lower order reagents, RCu(CN)MgBr, have also been carried out.Evidence is presented suggesting that species 2, unlike their dilithio analogs, are not discrete.
- Lipshutz, Bruce H.,Parker, David A.,Nguyen, Sam L.,McCarthy, Keith E.,Barton, John C.,et al.
-
p. 2873 - 2880
(2007/10/02)
-
- Substitution Reactions of Secondary Halides and Epoxides with Higher Order, Mixed Organocuprates, R2Cu(CN)Li2: Synthetic, Stereochemical, and Mechanistic Aspects
-
Higher order cuprates, represented by the general formula R2Cu(CN)Li2, are readily prepared from copper cyanide and 2 equiv of an organolithium.These novel reagents react readily and efficiently with secondary unactivated iodides and bromides affording products of substitution.Likewise, mono-, di-, and trisubstituted epoxides undergo ring opening leading to the corresponding alcohols in excellent yields.The effects of solvent, temperature, gegenion, and variations in ligands are discussed.Replacement of the second equivalent of RLi by CH3Li strongly encouragestransfer of R over CH3 in R(CH3)Cu(CN)Li2 with halides.Use of PhLi as RRLi in place of one RTLi (i.e.RT(Ph)Cu(CN)Li2) is suggested for oxirane cleavage.The stereochemical implications associated with both couplings are also addressed.
- Lipshutz, Bruce H.,Wilhelm, Robert S.,Kozlowski, Joseph A.,Parker, David
-
p. 3928 - 3938
(2007/10/02)
-
- CROSS-COUPLING REACTION OF SECONDARY ALKYL GRIGNARD REAGENTS WITH ALLYLIC ALCOHOLS CATALYZED BY DICHLOROPALLADIUM(II)
-
Dichloropalladium(II) was found to catalyze the reaction of allylic alcohols with 2-octylmagnesium chloride and 1-phenylethylmagnesium chloride to give the corresponding cross-coupling products in high yields.
- Hayashi, Tamio,Konishi, Mitsuo,Kumada, Makoto
-
-