Copper-Catalyzed Intramolecular Carbotrifluoromethylation of Alkynes for the Construction of Trifluoromethylated Heterocycles

Recent progress in aryltrifluoromethylation reactions of carbon-carbon multiple bonds

Due to the increasing relevance of fluorine-containing organic molecules in drug design, the synthesis of organofluorine compounds has gained high significance in synthetic organic chemistry. Trifluoromethylative difunctionalizations of carbon-carbon multiple bonds, with the simultaneous incorporation of a CF 3 group and another functional element, have considerable potential. Because of the high importance of carbon-carbon bond-forming reactions in organic synthesis, carbotrifluoromethylations and, in particular, aryltrifluoromethylations or heteroaryltrifluoromethylations are considered to be increasing fields of synthetic organic chemistry. The aim of the current review is to summarize recent developments of aryltrifluoromethylation or heteroaryltrifluoromethylation reactions.

Access to cyclopentenones via copper-catalyzed 5-endo trifluoromethylcarbocyclization of ynones

A copper-catalyzed 5-endo-selective trifluoromethylcarbocyclization of ynones is realized for the direct construction of trifluoromethylated cyclopentenones.

A diastereoselective synthesis of cyclopentanones via photocatalytic reductive alkyltrifluoromethylation of ynones

A photocatalytic reductive alkyltrifluoromethylation of ynones with the Langlois reagent is developed, providing a regio- and diastereoselective access to trifluoromethylated cyclopentanones under mild conditions.

Copper-Catalyzed Trifluoromethylation of Ynones Coupled with Dearomatizing Spirocyclization of Indoles: Access to CF3-Containing Spiro[cyclopentane-1,3'-indole]

A one-pot protocol for the Cu(I)-catalyzed difunctionalization of indolyl ynones has been achieved via trifluoromethylation of alkyne followed by dearomatizing spirocyclization of indoles. This cascade process enables constructing diverse CF₃-containing spiro[cyclopentane-1,3'-indole] scaffolds in moderate to excellent yields which have challenging quaternary spirocyclic carbon and tetrasubstituted alkenes.

Iridium-Catalyzed Regioselective Synthesis of Trifluoromethylated Isocoumarins through Annulation of Benzoic Acids with Trifluoromethylated Alkynes

An unprecedented Ir-catalyzed oxidative coupling of benzoic acids with trifluoromethylated alkynes was successfully developed to provide diverse trifluoromethylated isocoumarins in moderate to good yields. This new practical procedure was highlighted by mild reaction conditions, broad substrate scope, good regioselectivity, high efficiency, and easy operation.

Sulfur-Mediated Electrophilic Cyclization of Aryl-Substituted Internal Alkynes

A sulfur-mediated electrophilic cyclization reaction of aryl-tethered internal alkynes has been developed. Triflic anhydride-activated sulfoxides induced the electrophilic cyclization and then demethylation with triethylamine in one pot, affording 3-sulfenyl-1,2-dihydronaphthalenes and related types of products in yields of ≤96%.

A catalytic asymmetric one-pot [3+2] cyclization/semipinacol rearrangement sequence: an efficient construction of a multi-substituted 3H-spiro[benzofuran-2,1′-cyclopentane] skeleton

We report an asymmetric construction of multi-substituted 3H-spiro[benzofuran-2,1’-cyclopentane]s with three new stereocenters and two new ring systems.

Cu-Catalyzed C-H Trifluoromethylation of 3-Arylprop-1-ynes for the Selective Construction of Allenic Csp(2)-CF3 and Propargyl Csp(3)-CF3 Bonds

A new method has been developed for the Cu-catalyzed C-H trifluoromethylation of 3-arylprop-1-ynes for the selective construction of allenic Csp(2)-CF3 and propargyl Csp(3)-CF3 bonds. The selective formation of allenic Csp(2)-CF3 and propargyl Csp(3)-CF3 bonds can be controlled by modifying the reaction conditions.

Advances in Synthetic Applications of Hypervalent Iodine Compounds

The preparation, structure, and chemistry of hypervalent iodine compounds are reviewed with emphasis on their synthetic application. Compounds of iodine possess reactivity similar to that of transition metals, but have the advantage of environmental sustainability and efficient utilization of natural resources. These compounds are widely used in organic synthesis as selective oxidants and environmentally friendly reagents. Synthetic uses of hypervalent iodine reagents in halogenation reactions, various oxidations, rearrangements, aminations, C-C bond-forming reactions, and transition metal-catalyzed reactions are summarized and discussed. Recent discovery of hypervalent catalytic systems and recyclable reagents, and the development of new enantioselective reactions using chiral hypervalent iodine compounds represent a particularly important achievement in the field of hypervalent iodine chemistry. One of the goals of this Review is to attract the attention of the scientific community as to the benefits of using hypervalent iodine compounds as an environmentally sustainable alternative to heavy metals.

Direct vicinal difunctionalization of alkynes through trifluoromethylation and aminosulfonylation via insertion of sulfur dioxide under catalyst-free conditions

Direct vicinal difunctionalization of alkynes through a catalyst-free four-component reaction of Togni's reagent, alkynes, sulfur dioxide, and hydrazines at room temperature is developed, which generates (E)-3,3,3-trifluoroprop-1-ene-1-sulfonohydrazides in good yields.

Copper-catalyzed trifluoromethylation of alkenes: synthesis of trifluoromethylated benzoxazines

A ligand and base free copper catalyzed method has been developed for the construction of trifluoromethylated benzoxazines by using Umemoto's reagent.

Copper-catalyzed stereoselective oxytrifluoromethylation of propargyl amides for the construction of oxazolines

Copper-catalyzed stereoselective oxytrifluoromethylation of terminal propargyl amides was investigated for the construction of oxazolines under mild conditions.

Copper-catalyzed difunctionalization of activated alkynes by radical oxidation-tandem cyclization/dearomatization to synthesize 3-trifluoromethyl spiro[4.5]trienones

A copper-catalyzed difunctionalizing trifluoromethylation of activated alkynes with the cheap reagent sodium trifluoromethanesulfinate (NaSO2CF3 or Langlois' reagent) has been developed incorporating a tandem cyclization/dearomatization process. This strategy affords a straightforward route to synthesis of 3-(trifluoromethyl)-spiro[4.5]trienones, and presents an example of difunctionalization of alkynes for simultaneous formation of two carbon-carbon single bonds and one carbon-oxygen double bond.