Asymmetric Cyanation with the Chiral Ru-Li Combined Catalysts

The combined systems of phenylglycinate/BINAP/Ru(II) complex and Li compounds have been found to act as highly reactive and enantioselective catalysts for cyanosilylation and hydrocyanation of aldehydes, α-keto esters, α,β-unsaturated ketones, and N-protected aldimines. In this account, we describe the concept of catalyst design, the catalytic efficiency of the novel combined systems in the asymmetric cyanation, and the proposed reaction pathway based on the spectral analysis data. 1 Introduction. 2 Cyanosilylation of Aldehydes and Ketones Catalyzed by LiCl. 3 Asymmetric Cyanosilylation of Aldehydes and α-Keto Esters. 3.1 Design of Chiral Ru-Li Combined Catalyst Systems. 3.2 Cyanosilylation of Aldehydes. 3.3 Cyanosilylation of α-Keto Esters. 4 Asymmetric Hydrocyanation of Aldehydes, α,β-Unsaturated Ketones, and Aldimines. 4.1 Hydrocyanation of Aldehydes. 4.2 Conjugate Cyanation of α,β-Unsaturated Ketones. 4.3 Strecker-Type Reaction. 5 Mechanistic Considerations for Cyanosilylation of Aldehydes and Ketones. 5.1 Achiral Reaction Catalyzed by LiCl. 5.2 Asymmetric Reaction with the Chiral Ru-Li Combined Catalyst. 6 Conclusion

Efficient cross-coupling reaction of functionalized alkyl bromides with aryl halides by using electrochemical method

Highly reactive zinc metal was readily prepared by electrolysis of a DMF solution containing naphthalene and a supporting electrolyte in a one-compartment cell fitted with a platinum cathode and a zinc anode. This reactive zinc (EGZn/Naph) was used for transformation of bromoalkanes into the corresponding organozinc bromides, which can not be achieved by the use of usual zinc metals. Reaction of the organozinc compounds thus prepared with various aryl iodides in the presence of 5 mol% of palladium catalyst gave the corresponding cross-coupling products in hick yields. Arylzinc iodides were also prepared by the use of EGZn/Naph and they were reacted with other aryl iodides to give the corresponding cross-coupled biaryl in good yields

Highly reactive electrogenerated zinc: preparation and its use in cross-coupling reactions

Highly reactive zinc metal was prepared by electrolysis of a N, N-dimethylformamide (DMF) solution containing naphthalene and a supporting electrolyte in a one-compartment cell fitted with a platinum cathode and a zinc anode. This highly reactive electrogenerated zinc (EGZn/Naph) was used for transformation of bromoalkanes into the corresponding organozinc bromides, which cannot be achieved by the use of usual zinc metals. Reaction of the organozinc compounds were thus prepared with various aryl iodides in the presence of 5 mol% of palladium catalyst to give the corresponding cross-coupling products in high yields. Arylzinc iodides were also prepared by the use of this highly reactive zinc, and they were reacted with other iodides to give the corresponding cross-coupled biaryls in good yields

Determination of optimum conditions in preparing highly reactive electrogenerated zinc by gas chromatograph

Highly reactive electrogenerated zinc metal (EGZn/Naph) was readily prepared by electrolysis of a DMF solution cotaining naphthalene and a supporting electrolyte in a one-compartment cell fitted with a platinum cathode and a zinc anode. The reactivity of this EGZn/Naph elucidated by an efficient transformation of ethyl 2-bromolbutanoate as a model substrate into the corresponding organozinc compound, which can not be achieved by the use of usual zinc metal. It was found that the electrolysis at -10C at a constant current of 60 mA/cm2 under nitrogen atmosphere was the optimum conditions in preparing of the EGZn/Naph

Determination of structure of precursor of ibuprofen: purification and analysis

(S)-2-(p-isobutylphenyl) propanoic acid, so called ibuprofen, is one of the most popular anti-inflammatory agents. An efficient cross-coupling reaction of organozinc compound of ethyl 2-bromoacrylate, prepared by the reaction of hightly reactive zinc was carried out with aryl iodide to synthesize 2-(4-isobutylphenyl)-propenoate, a precursor of ibuprofen. Highly reactive zinc metal (EGZn/Naph) was readily prepared by electrolysis of a DMF solution containing naphthalene and a supporting electrolyte in a one-compartment cell fitted with a platinum cathode and a zinc anode. The synthesized precursor of ibuprofen was purified by thin layer chromatography on silica gel and its structure was confirmed by elemental analysis, mass, IR, 1H NMR and 13C NMR spectroscopic analysis

Synthesis of precursor of anti-cancer drugs

Highly reactive electrogenerated zinc metal (EGZn/Naph) was readily prepared by electrolysis of a DMF solution containing naphthalene and a supporting electrolyte in a one-compartment cell fitted with a platinum cathode and a zinc anode. This reactive zinc was used for efficient transformation of ethyl 2-bromoacrylate into the corresponding organozinc compound, which was reacted with various aryl halides in the presence of palladium catalyst to give the corresponding cross-coupling products, ethyl 2-arylpropenoates, in high yields. These cross-coupling reactions were successfully applied to a synthesis of the precursors of non-steroidal anti-inflammatory drugs such as ibuprofen, ketoprofen and ioxoprofen, which recently, have been shown to decrease the risk of cancer

Asymmetric Hydrogenation of Aromatic Heterocyclic Ketones Catalyzed by the MsDPEN–Cp*Ir(III) Complex

Asymmetric hydrogenation of aromatic heterocyclic ketones catalyzed by Cp*Ir(OTf)(Msdpen) (MsDPEN = N-(methanesulfonyl)-1,2-diphenylethylenediamine) affords the heterocyclic alcohols in 93% to > 99% ee. The reaction is conducted in a methanolic solution with a substrate-to-catalyst molar ratio of 200-5000 under 15 atm of H2. The heterocyclic rings of substrates are left intact