Preparation of Secondary Alkyl and Benzylic Zinc Bromides Using Activated Zinc Metal Deposited on Titanium Oxide

Stadtmüller, Heinz; Greve, Björn; Lennick, K.; Chair, Abdellatif; Knöchel, Paul

doi:10.1055/s-1995-3855

Cited by 35 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although this Negishi protocol has been extensively studied using alkynyl,133 aryl, alkenyl,34,117,134 methyl,135 allyl,136 and benzylzinc30,65,90,137 reagents, the frequent use of more challenging alkylzinc reagents containing β-hydrogen(s) as a cross-coupling partner has only evolved more recently. Our discussion in this section will be limited to the use of alkylzinc reagents as cross-coupling partners in Pd(0) catalysis and are generally presented in chronological order.…”

Section: Alkylzinc Reagentsmentioning

confidence: 99%

“…The Normant group reported the preparation of alkylzinc using Et 2 O as solvent . Alternative methods of metal activation include washing with aqueous HCl, using Zn−Cu − Zn−Cu−Ag couples, , or Zn−Hg alloys, ultrasound irradiation, metal−solvent co-condensation, , sacrificial Zn anodes, pulsed sonoelectro-chemical reduction of zinc salts, and reduction of zinc salts on titanium dioxide . A wide range of organic functionalities, such as esters, ,− ketones, , cyanides, ,− ,,− ,− halides, ,,,,, N , N -bis(trimethylsilyl)amino groups, primary and secondary amino groups, amides and phthalimides, , sulfoxides, sulfides, sulfones, , thioesters, boronic esters, ,, enones, , and phosphates , are compatible under this mild zinc insertion protocol (Figure a).…”

Section: Alkylzinc Reagentsmentioning

confidence: 99%

See 1 more Smart Citation

Advances in Transition Metal (Pd,Ni,Fe)-Catalyzed Cross-Coupling Reactions Using Alkyl-organometallics as Reaction Partners

2011

View full text Add to dashboard Cite

Introduction 1418 1.1. List of Common Ligands 1419 2. Alkylzinc Reagents 1419 2.1. Synthesis of Alkylzinc Reagents 1419 2.2. Stability of Alkylzinc Reagents 1420 2.3. Cross-Coupling Reactions of Alkylzinc Reagents 1421 2.4. Palladium-Catalyzed Cross-Coupling Reactions of Alkylzinc Reagents 1423 2.4.1. Palladium-Catalyzed C(sp 2 )-C(sp 3 ) Negishi Coupling with Alkylzinc Reagents 1423 2.4.2. Palladium-Catalyzed C(sp 3 )-C(sp 3 ) Negishi Coupling with Alkylzinc Reagents 1427 2.4.3. Palladium-Catalyzed C(sp)-C(sp 3 ) Negishi Coupling with Alkylzinc Reagents 1428 2.4.4. Formation of Ketones via Palladium-Catalyzed Negishi Coupling with Alkylzinc Reagents 1429 2.5. Nickel-Catalyzed Cross-Coupling Reactions of Alkylzinc Reagents 1429 2.5.1. Nickel-Catalyzed C(sp 2 )-C(sp 3 ) Negishi Coupling with Alkylzinc Reagents 1429 2.5.2. Nickel-Catalyzed Carboxylations with Alkylzinc Reagents 1430 2.5.3. Nickel-Catalyzed C(sp 3 )--(sp 3 ) Negishi Coupling with Alkylzinc Reagents 1430 2.5.4. Mechanistic Insights in Nickel-Catalyzed Cross-Couplings 1433 3.

show abstract

Section: Alkylzinc Reagentsmentioning

confidence: 99%

Section: Alkylzinc Reagentsmentioning

confidence: 99%

Advances in Transition Metal (Pd,Ni,Fe)-Catalyzed Cross-Coupling Reactions Using Alkyl-organometallics as Reaction Partners

2011

View full text Add to dashboard Cite

show abstract

“…The reaction, however, was limited by the low reactivity of the metal, and thus, several methods were developed to increase the reactivity of Zn and to expand the scope of oxidative addition to less reactive C–X bonds. These methods of activation include washing Zn metal with aqueous HCl,18 addition of 1,2‐dibromoethane19 and/or chlorotrimethylsilane,20 ultrasound irradiation,21 metal‐solvent co‐condensation,22 and reduction of zinc salts on titanium dioxide 23. Despite these forays, direct oxidative addition of Zn metal to organic halides has been limited to relatively reactive electrophiles, including alkyl iodides and α‐halo esters.…”

Section: Preparation Of Organozinc Halide Reagentsmentioning

confidence: 99%

Synthesis and Thermodynamic Studies of Oligonucleotides Containing the Two Isomers of Thymine Glycol

Iwai

2001

Chem. Eur. J.

View full text Add to dashboard Cite

Thymine glycol is a major type of base damage, which is formed in DNA by reactive oxygen species. I describe the synthesis of oligonucleotides containing the 5S isomer of thymine glycol, which was not obtained by the oxidation of the oligonucleotides. Before the 5S isomer was synthesized, a building block without the protection of the tertiary hydroxy function at the C5 position of thymine glycol was tested by the use of the previously reported 5R isomer. In the presence of imidazole, migration of the silyl group between the C5 and C6 positions was observed, while the result of the oligonucleotide synthesis was identical to the case of the fully protected building block. Therefore, oligonucleotides containing the (5S)-thymine glycol were synthesized with the disilylated building block. In contrast to the 5R derivative, two products were detected in the HPLC analysis of the crude mixture after deprotection. Analysis by matrix-assisted laser-desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry revealed that the larger peak was the desired oligonucleotide, and it was found that the by-product was completely degraded by a short treatment with ammonium hydroxide at room temperature. I also report the application of oligonucleotides containing each isomer of thymine glycol to thermodynamic analyses of base-pair formation. The thermodynamic parameters obtained for the duplexes containing either the (5R)- or (5S)-thymine glycol indicated that the thymine glycol cannot form a base-pair with any nucleobase, regardless of the configuration at the C5 position.

show abstract

“…treated with 1,2-dibromoethane and TMSCl (trimethylsilyl chloride) in THF at 40 • C [6e, 18,19]. Secondary alkyl iodides react with zinc dust even at 25 • C [6e, 19,20], whereas benzylic bromides undergo an optimal insertion reaction at 0 • C [21]. Organozinc formation from alkyl chlorides, bromides, sulfonates, and phosphates can be achieved in the presence of Zn(0) in polar solvents by adding a catalytic amount of alkali metal iodide or a stoichiometric amount of an alkali metal bromide [22].…”

Section: Direct Insertion Of Zn(0) Into Organohalidesmentioning

confidence: 99%

Carbon–Carbon Bond Forming Reactions Mediated by Organozinc Reagents

Chemla

Ferreira

Jackowski

et al. 2013

Metal‐Catalyzed Cross‐Coupling Reactions and More

View full text Add to dashboard Cite

Preparation of Secondary Alkyl and Benzylic Zinc Bromides Using Activated Zinc Metal Deposited on Titanium Oxide

Cited by 35 publications

References 0 publications

Advances in Transition Metal (Pd,Ni,Fe)-Catalyzed Cross-Coupling Reactions Using Alkyl-organometallics as Reaction Partners

Advances in Transition Metal (Pd,Ni,Fe)-Catalyzed Cross-Coupling Reactions Using Alkyl-organometallics as Reaction Partners

Synthesis and Thermodynamic Studies of Oligonucleotides Containing the Two Isomers of Thymine Glycol

Carbon–Carbon Bond Forming Reactions Mediated by Organozinc Reagents

Contact Info

Product

Resources

About