Rhodium-Catalyzed Synthesis Research Articles

Rhodium-Catalyzed Synthesis of Trifluoromethyl-Containing Allylic Alcohols Via Z-Alkenyl Transfer with High Stereochemistry Retention.

Herein, we report the rhodium-catalyzed Z-alkenyl transfer from tertiary allylic alcohols to aryl trifluoromethyl ketones, which provided an efficient way of preparation of trifluoromethyl-containing Z-allylic alcohols via β-Z-alkenyl elimination. The key Z-alkenyl-rhodium species were generated with a high degree of stereochemical retention. This reaction featured a broad substrate scope and good functional tolerance and would offer a fascinating approach for the synthesis of Z-alkenes.

Rhodium-Catalyzed Synthesis of Phenanthrenes from Biarylboronic Acids and Sulfoxonium or Iodonium Ylides

Rhodium-Catalyzed Synthesis of Phenanthrenes from Biarylboronic Acids and Sulfoxonium or Iodonium Ylides

Rhodium-catalyzed synthesis of Si-stereogenic alkoxysilanes and silyl enol ethers via hydrosilylation of carbonyl compounds.

A highly efficient rhodium-catalyzed asymmetric hydrosilylation of aldehydes, ketones, and α,β-unsaturated ketones with dihydrosilanes is developed, that allows the rapid assembly of a variety of Si-stereogenic alkoxysilanes and silyl enol ethers in good yields and enantioselectivities under mild conditions. The applicability of this methodology was demonstrated by a series of stereospecific transformations to construct diverse Si-stereogenic derivatives.

Cobalt- or rhodium-catalyzed synthesis of 1,2-dihydrophosphete oxides via C-H activation and formal phosphoryl migration.

A highly stereo- and chemoselective intermolecular coupling of diverse heterocycles with dialkynylphosphine oxides has been realized via cobalt/rhodium-catalyzed C-H bond activation. This protocol provides an efficient synthetic entry to functionalized 1,2-dihydrophosphete oxides in excellent yields via the merger of C-H bond activation and formal 1,2-migration of the phosphoryl group. Compared with traditional methods of synthesis of 1,2-dihydrophosphetes that predominantly relied on stoichiometric metal reagents, this catalytic system features high efficiency, a relatively short reaction time, atom-economy, and operational simplicity. Photophysical properties of selected 1,2-dihydrophosphete oxides are also disclosed.

Rhodium-Catalyzed Synthesis of Chiral trans-γ‑Lactams through Dynamic Kinetic Resolution

Key words rhodium catalysis - asymmetric arylation - chiral diene ligands - polysubstituted lactams

Rhodium-Catalyzed Synthesis of 2-Methylindoles via C-N Bond Cleavage of N-Allylbenzimidazole.

A rhodium-catalyzed oxidative C-H/N-H dehydrogenative [3 + 2] annulation strategy has been reported between anilines and N-allylbenzimidazole for the synthesis of 2-methylindole scaffolds. An N-allylbenzimidazole has been used as a 2C synthon for the synthesis of indole, and more importantly, this transformation involves the cleavage of the thermodynamically stable C-N bond of allylamine. Detailed mechanistic studies have been performed and a key intermediate was detected in HRMS. This transformation proceeds through a cascade of C(sp2)-H allylation followed by intramolecular cyclization.

Synthesis of Dihydro-3,1-benzoxazine Derivatives from 1,3-Amino Alcohols and N-Sulfonyl-1,2,3-triazole.

An efficient rhodium-catalyzed synthesis of dihydro-3,1-benzoxazine derivatives has been accomplished from aniline-derived 1,3-amino alcohols and N-sulfonyl-1,2,3-triazole. The developed reaction demonstrates the new reactivity of azavinyl carbenes and allows access to diverse substituted dihydro-3,1-benzoxazines in good yields. Importantly, the reaction was readily extended to diols and could be used for selective protection of amino alcohols with N-sulfonyl-1,2,3-triazole as the protecting reagent.

Enantioselective Rhodium-Catalyzed Synthesis of Cyclobutene Derivatives Using Boronic Acids

Key words rhodium catalysis - boronic acids - cyclobutanone ketals

Rhodium-catalyzed C-H carboxymethylation of anilines with vinylene carbonate.

A rhodium-catalyzed synthesis of phenylacetate has been realized by direct C-H carboxymethylation of anilines bearing removable directing groups. The reaction occurred most efficiently in air, without any external base or oxidant. This methodology is expected to provide a facile and general access to various bioactive 2-amino aromatic acetic acid derivatives.

Rhodium-Catalyzed Synthesis of Peptide Polysulfides by Insertion of Sulfur into Unprotected Peptide Disulfides.

A rhodium-catalyzed insertion of sulfur into unprotected peptide disulfides in aqueous solvents has been developed, which yields mixtures of trisulfides and tetrasulfides. This method can be applied to peptides containing amino acids such as Gly, Phe, Tyr, Ser, Met, Asp, Gln, and Lys and provides polysulfides with various amino acid residues without being affected by functional groups. A reaction can be conducted on a gram scale. Vasopressin can also be converted into its corresponding polysulfides.

Rhodium-Catalyzed C2-Alkylation of Indoles with Cyclopropanols Using N,N-Dialkylcarbamoyl as a Traceless Directing Group.

An efficient rhodium-catalyzed synthesis of C2-alkylated NH-free indoles has been achieved from substituted indoles and cyclopropanols. The reaction allows the synthesis of various C2-alkylated products in good to excellent yield. Important features of the method include the use of a N,N-dialkylcarbamoyl group as a traceless directing group, C-H/C-C bond functionalization, good functional group tolerance, broad scope, synthesis of pyrrolo[1,2-a]indole, and identification of potential intermediates.

Rhodium-Catalyzed Synthesis of N-Arylaziridines

Key words aziridines - rhodium catalysis - chemoselectivity - diastereoselectivity - nitroarenylamines - cyclooctenes

Rhodium-Catalyzed Synthesis of Unsymmetric Di(heteroaryl)ureas Involving an Equilibrium Shift

Unsymmetric di(heteroaryl)ureas such as HetAr1-NHCONH-HetAr2 are efficiently synthesized from two symmetric ureas, HetAr1-NHCONH-HetAr1 and HetAr2-NHCONH-HetAr2, by rhodium-catalyzed exchange reactions. The equilibrium in some of the reactions can be shifted to the formation of unsymmetric ureas by the aggregation of the dimers formed by inter- and intramolecular hydrogen bonding.

Rhodium-Catalyzed α-Tetrasubstituted α-Amino Acid Synthesis

Rhodium-Catalyzed α-Tetrasubstituted α-Amino Acid Synthesis

Enantioselective Rhodium-Catalyzed Synthesis of Fluorinated Allenes

Key words rhodium catalysis - enantioselectivity - organozinc - fluoroallenes

Rhodium-Catalyzed Synthesis of 2-Aroylpyrimidines via Cascade Heteropolyene Rearrangement.

A one-step synthesis of cytotoxic 2-aroylpyrimidines by the denitrogenative reaction of 1-tosyl-1,2,3-triazoles with isoxazoles under rhodium catalysis has been developed. According to the density functional theory calculations and control experiments, the disclosed reaction proceeds via the rearrangement of an oxadiazatetraene intermediate involving a cascade of intramolecular aza-Diels-Alder and retro-aza-Diels-Alder reactions. The presence of a substituent at C4 of the isoxazole is a prerequisite for the formation of the pyrimidines.

Rhodium-Catalyzed Synthesis of β2/γ2/δ2-Amino Acid Derivatives

Key words amino acid derivatives - rhodium catalysis - boronic acids - hydroarylation

Rhodium-Catalyzed Synthesis of Chiral 3,4-Fused Tricyclic Indoles

Key words enones - diazomalonates - rhodium catalysis - cycloheptindoles - asymmetric catalysis

Rhodium-Catalyzed Synthesis of 1,3-Benzodiazepines

Rhodium-Catalyzed Synthesis of 1,3-Benzodiazepines

Rhodium-Catalyzed Synthesis of Chiral Hydrophenanthridinones

Key words methoxybenzamides - quinones - rhodium catalysis - C–H activation - asymmetric catalysis - phenanthridinones