Rhodium-Catalyzed Synthesis Research Articles

Rhodium-Catalyzed Synthesis of 1H‑Indole-2,3-dicarboxylates from Arylhydrazines and Maleates

Rhodium-Catalyzed Synthesis of 1H‑Indole-2,3-dicarboxylates from Arylhydrazines and Maleates

Rhodium-Catalyzed Synthesis of Organosulfur Compounds Involving S-S Bond Cleavage of Disulfides and Sulfur.

Organosulfur compounds are widely used for the manufacture of drugs and materials, and their synthesis in general conventionally employs nucleophilic substitution reactions of thiolate anions formed from thiols and bases. To synthesize advanced functional organosulfur compounds, development of novel synthetic methods is an important task. We have been studying the synthesis of organosulfur compounds by transition-metal catalysis using disulfides and sulfur, which are easier to handle and less odiferous than thiols. In this article, we describe our development that rhodium complexes efficiently catalyze the cleavage of S-S bonds and transfer organothio groups to organic compounds, which provide diverse organosulfur compounds. The synthesis does not require use of bases or organometallic reagents; furthermore, it is reversible, involving chemical equilibria and interconversion reactions.

Rhodium-Catalyzed Synthesis of α-Amino Acid Derivatives

Rhodium-Catalyzed Synthesis of α-Amino Acid Derivatives

Rhodium-Catalyzed Synthesis of Enantioenriched Phthalides

Key words phthalides - rhodium catalysis - C–H activation - asymmetric catalysis

Rhodium-Catalyzed Synthesis of Isoquinolines from Aryl Ketones and Alkynes

Key words rhodium catalysis - hydroxylamine sulfonic acid - alkynes - ketones - isoquinolines - one-pot synthesis

Modular Rhodium-Catalyzed Synthesis of Quinolines from Anthranils and Acrylic Acids

Modular Rhodium-Catalyzed Synthesis of Quinolines from Anthranils and Acrylic Acids

Theoretical study of rhodium(III)-catalyzed synthesis of benzoxepine and coumarin.

The mechanisms of the rhodium-catalyzed cycloaddition of 2-vinylphenol with diphenylacetylene and carbon monoxide have been studied using density functional theory calculations at the B3LYP/6-31G (d, p) (Lanl2dz for Rh) level of theory. The SMD solvation model was used in MeCN solvents at M06-2X/6-311 ++ G (d, p) (Lanl2dz (f) for Rh) levels using a single-point calculation to consider the solvent effect. The calculation results show that there are two competitive reaction pathways for the cycloaddition reaction of rhodium-catalyzed synthesis of benzohexine and coumarin. Starting from the precursor reaction complex, the reaction channel is more favorable for the carbon atoms of diphenylacetylene and carbon monoxide to attack the Rh-C bond (the barriers of 9.88 and 10.01kcal/mol) rather than attack the Rh-O bond (the barriers of 15.37 and 30.17kcal/mol), and carbon monoxide in two different reaction channels has a greater energy difference than diphenylacetylene. The results show that the computational study of the rhodium-catalyzed cycloaddition reaction has a high catalytic activity consistent with the high yield of the experiment of Gulías et al.

Rhodium-Catalyzed Asymmetric Synthesis of Axially Chiral Polyaromatic Hydrocarbons

Rhodium-Catalyzed Asymmetric Synthesis of Axially Chiral Polyaromatic Hydrocarbons

Rhodium-Catalyzed Synthesis of α-Amino Acid Derivatives

Rhodium-Catalyzed Synthesis of α-Amino Acid Derivatives

Pyridotriazole as Carbene Precursor in Rhodium-Catalyzed Synthesis of 3H-Indoles

Pyridotriazole as Carbene Precursor in Rhodium-Catalyzed Synthesis of 3H-Indoles

Rhodium-Catalyzed Synthesis of Chiral Sulfoximines and 1,2-Benzothiazines

Key words sulfoximines - benzothiazines - rhodium catalysis - kinetic resolution - asymmetric catalysis

Rhodium-Catalyzed Synthesis of Amides from Functionalized Blocked Isocyanates

Isocyanates are useful building blocks for the synthesis of amides, although their widespread use has been limited by their high reactivity, which often results in poor functional group tolerance and a propensity to oligomerize. Herein, a rhodium-catalyzed synthesis of amides is described coupling boroxines with blocked (masked) isocyanates. The success of the reaction hinges on the ability to form both the isocyanate and the organorhodium intermediates in situ. Relying on masked isocyanate precursors and on the high reactivity of the organorhodium intermediate results in broad functional group tolerance, including protic nucleophilic groups such as amines, anilines, and alcohols.

Rhodium-Catalyzed Synthesis of Organosulfur Compounds using Sulfur

Sulfur is one of the few elements that occurs uncombined in nature. Sulfur atoms are found in natural amino acids and vitamins. In the chemical industry, organosulfur compounds are used for fabricating rubber, fibers, and dyes, pharmaceuticals, and pesticides. Although sulfur, which is cheap and easy to handle, is a useful source of sulfur atom in functional organosulfur compounds, it is rarely used in organic synthesis. Activation of sulfur by high temperature, light irradiation, treatment with nucleophiles and electrophiles, and redox conditions often results in the formation of various active sulfur species, which complicate reactions. The development of a method that mildly activates sulfur is therefore desired. The use of transition-metal catalysts is a new method of activating sulfur under mild conditions, and, in this article, we describe the rhodium-catalyzed synthesis of various organosulfur compounds by the insertion of sulfur atoms into single bonds and by the addition of sulfur to unsaturated bond in various organic compounds.1 Introduction2 Sulfur Activation without using Transition Metal3 Transition-Metal-Catalyzed Activation of Sulfur4 Rhodium-Catalyzed Reactions using Sulfur4.1 Rhodium-Catalyzed Sulfur Atom Exchange Reactions using Sulfur4.2 Synthesis of Diaryl Sulfides using Rhodium-Catalyzed Exchange Reaction of Aryl Fluorides and Sulfur/Organopolysulfides4.3 Rhodium-Catalyzed Synthesis of Isothiocyanate using Sulfur4.4 Rhodium-Catalyzed Sulfur Addition Reaction to Alkenes for Thiiranes Synthesis4.5 Rhodium-Catalyzed Sulfur Addition Reaction to Alkynes for 1,4-Dithiins Synthesis5 Conclusion

Enantioselective Rhodium-Catalyzed Synthesis of C–N Axially Chiral N-Aryloxindoles

Key words rhodium catalysis - C–H activation - N-aryloxindoles - axial chirality

Rhodium-catalysed synthesis of fused pyrimidine derivatives employing N-sulfonyl-1,2,3-triazoles as a 1-aza-[4C] synthon

A new synthetic application of N-sulfonyl-1,2,3-triazoles acting as a 1-aza-[4C] synthon via the 1,2-shift reaction of an α-imine rhodium carbene was developed for the synthesis of fused pyrimidine derivatives. The high reactivity of the strained three-membered 2H-azirine ring facilitated the unusual cyclization of electron-deficient dienes with electron-deficient dienophiles. The compatibility was good with common functionalities tolerated. Excellent chemoselectivity was observed, and no reactions occurred between the rhodium carbene and 2H-azirine. The products could be converted into seven-membered multi-functionalized 1H-1,4-diazepine derivatives, illustrating the potential application of the protocol in medium-sized N-heterocycle synthesis.

Rhodium-catalyzed synthesis of unsymmetric di(heteroaryl) compounds via heteroaryl exchange reactions

Unsymmetric di(heteroaryl) HetAr–X–HetAr′ compounds have flexible and rigid groups, and are expected to exhibit various biological activities by interacting with proteins and nucleic acids. Then, synthesis of such compounds is critical for the development of drugs. Unsymmetric HetAr-X-HetAr′ compounds were efficiently synthesized by rhodium-catalyzed heteroaryl exchange reactions, which involved equilibrium control by judicious design of organic heteroaryl reagents. This method allows synthesis of unsymmetric HetAr–O–HetAr′, HetAr–S–HetAr′, and HetAr–CH2–HetAr′ compounds as well as HetAr–F compounds from heteroaryl aryl ethers and heteroaryl reagents. The rhodium-catalyzed heteroaryl exchange reaction was also applied to the synthesis of C–N-linked di(heteroaryl) compounds from N-benzoyl heteroarenes and heteroaryl aryl ethers. The synthesis has a broad applicability, which gives a diversity of novel unsymmetric HetAr–X–HetAr′ and C–N-linked di(heteroaryl)s compounds containing five- and six-membered heteroarenes.

Rhodium-Catalyzed Synthesis of Blue-Emitters

Rhodium-Catalyzed Synthesis of Blue-Emitters

Rhodium-Catalyzed Synthesis, Crystal Structures, and Photophysical Properties of [6]Cycloparaphenylene Tetracarboxylates.

The synthesis of C2-symmetrical [6]cycloparaphenylene (CPP) tetracarboxylates has been achieved via macrocyclization by the rhodium-catalyzed intermolecular stepwise cross-alkyne cyclotrimerization and subsequent reductive aromatization. The 1H NMR spectra of the thus-obtained C2-symmetrical [6]CPP-tetracarboxylates revealed that the rotation of unsubstituted benzene rings is slow at room temperature. These [6]CPPs formed columnar packing structures, and their absorption maxima were significantly blue-shifted compared to that of nonsubstituted [6]CPP due to the presence of four electron-withdrawing ester moieties.

Rhodium-Catalyzed Synthesis of Carbazoles from Biarylboronic Acids

Key words aryl azides - boronic acids - rhodium catalysis - carbazoles - C–H activation

Rhodium-Catalyzed Asymmetric Synthesis of Tertiary α-Hydroxy Esters

Rhodium-Catalyzed Asymmetric Synthesis of Tertiary α-Hydroxy Esters