A one-pot synthesis of vicinal diamines using indoles, azoles and phenothiazines in a tandem multi-component reaction is developed.

Comprehensive Summary

A one-pot synthesis of vicinal diamines using indoles, azoles and phenothiazines in a tandem multi-component reaction is developed. The utilization of a copper-iodine co-catalytic system enables the generation of a diverse range of vicinal diaminoindoles with good selectivity and moderate to good yields. An attractive aspect of this method is that it can be conducted under mild and environmentally friendly conditions, showcasing its potential as an alternative approach for synthesizing vicinal diamines. Moreover, the use of a multicomponent tandem reaction highlights the power and versatility of such strategies in synthetic chemistry.

An efficient nickel-catalyzed cross-electrophile coupling of triazine esters with aryl bromides in the presence of magnesium powder and lithium chloride in THF is reported. The cross-coupling reactions proceeded smoothly at room temperature to afford a variety of structurally diverse diaryl ketones in moderate to good yields with wide functional group tolerance.

Comprehensive Summary

Cross-electrophile coupling of triazine esters with aryl bromides could be facilely accomplished by employing nickel as catalyst, magnesium as metal mediator, and lithium chloride as additive. The reactions proceeded efficiently in THF at room temperature through C—O bond activation to afford an array of structurally different diaryl ketones in moderate to good yields with wide functional group tolerance. Control experiments showed that nickel, magnesium, lithium chloride, and THF are all indispensable for the good performance of the coupling reaction. Preliminary mechanistic exploration indicated that in situ formed arylmagnesium reagent by the insertion of magnesium into aryl bromide might serve as the key intermediate of the cross-coupling. The method which avoids the utilization of moisture-labile and relatively difficult-to-obtain organometallics is step-economical, cost-efficient, and operationally simple, potentially serving as an attractive alternative to documented methods.

The first iron-catalyzed alkenylzincation of internal alkynes featuring mild conditions, simple operation, broad substrate scope, excellent functional group tolerance, and high activity has been developed, which provides an efficient access to multi-substituted conjugated olefins.

Comprehensive Summary

The alkenylzincation of internal alkynes is an effective method for the synthesis of multi-substituted conjugated dienes; however, the current catalytic systems for this reaction are limited in terms of substrate scope and selectivity control, which restricts its practical applications. Herein, we report the first iron-catalyzed alkenylzincation of internal alkynes, which features mild conditions, simple operation, broad substrate scope (including aryl/alkyl, diaryl, and dialkyl acetylenes), excellent functional group tolerance (tolerating highly active functional groups such as ester, methylthio, amide, sulfonyl, cyano, etc.), and high activity (with a turnover number of up to 11500, the highest record for carbometallation reactions). Notably, the catalytic system described in this article also realized the highly selective vinylzincation of unfunctionalized internal alkynes as well as the alkenylzincation of unsymmetrical diarylacetylenes and dialkyl acetylenes, which have not been achieved with other catalytic systems reported in the literatures. The current study provides a highly selective access to synthetically important multi-substituted conjugated dienes.

Direct alkylation with skipped enynes or cyclopropropylacetylenes represents an ideal process for the installation of pentadienyl group in terms of atom- and step-economy. We herein describe a synergistic chiral primary amine/Pd catalysis for asymmetric α-pentadienylation of β-ketocarbonyls and aldehydes with skipped enynes or cyclopropropylacetylenes. The reaction features the construction of acyclic all-carbon quaternary centers with high enantioselectivity, and good functional group tolerance and scalability.

Comprehensive Summary

Direct alkylation with skipped enynes or cyclopropropylacetylenes represents an ideal process for the installation of pentadienyl group in terms of atom- and step-economy. The development of catalytic asymmetric versions has been frequently pursued and most of the successes have been achieved with enolizable aldehydes. We herein describe a synergistic chiral primary amine/Pd catalysis for asymmetric α-pentadienylation of β-ketocarbonyls and aldehydes with skipped enynes or cyclopropropylacetylenes. The reaction features the construction of acyclic all-carbon quaternary centers with high enantioselectivity, and good functional group tolerance and scalability.

An efficient catalytic asymmetric synthesis of optically active 2,2'-dibromo-6,6'-diiodo -1,1'-biphenyl was reported. This chiral molecule features four carbon-halogen bonds, which can be sequentially elaborated to provide a variety of highly functionalized axially chiral biaryls.

Comprehensive Summary

The widespread applications of atropisomeric compounds have led to an increasing demand for their synthesis. Rather than synthesizing different functionalized atropisomers individually, an attractive alternative is to identify a key intermediate or precursor that can be readily elaborated and functionalized to realize divergent synthesis of this class of compounds. Building on our previous research on asymmetric ring-opening of cyclic diaryliodoniums, in this work we developed a copper-catalyzed enantioselective ring-opening reaction of ortho,ortho’-dibromo substituted cyclic diaryliodonium with lithium iodide. The resulting optically active product 2,2'-dibromo-6,6'-diiodo-1,1'-biphenyl, possessing two C—Br bonds and two C—I bonds, can be selectively advanced to form different functionalities. Remarkably, the utilities of the product were highlighted by successively demonstrating C—I and C—Br metalation, followed by carboxylation, boroylation, oxygenation, allylation, phosphinylation, etc., all of which provide a new and convenient approach to synthesizing a range of functionalized axially chiral biphenyls.

Comprehensive Summary

A series of 3-acyl-substituted isoindolinone derivatives were synthesized in one-pot manner via the reaction of o-bromobenzaldehydes, isocyanides, and carboxylic acids in the presence of palladium catalyst and base. The reaction employing easily available starting materials features simple operation and high efficiency. The mechanistic study showed that the reaction might undergo 1) Pd-catalyzed [3+2] cyclization of o-bromobenzaldehyde with isocyanide and the re-insertion of another molecule of isocyanide, 2) addition of carboxylic acid to in situ formed ketenimine followed by a rearrangement relay to give 3,3-diacyl-substituted isoindolinone derivative. Further transformations of the obtained products through decarbonylation could also be realized.

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