Emerging Applications of Aryl Trifluoromethyl Diazoalkanes and Diazirines in Synthetic Transformations.

Aryl trifluoromethyl diazoalkanes and diazirines have become unique as reactants in synthetic methodology. As privileged compounds containing CF groups and ease of synthetic access, aryl trifluoromethyl diazoalkanes and diazirines have been highlighted for their versatility in applications toward a wide range of synthetic transformations. This Perspective highlights the synthetic applications of these reactants as precursors of stabilized metal carbenes, i.

Fluoride-Triggered Synthesis of 1-Aryl-2,2-difluoroalkenes via Desilylative Defluorination of (1-Aryl)-2,2,2-trifluoroethyl-silanes.

An efficient route for the synthesis of 1-aryl-2,2-difluoroalkenes via 1,2-desilylative defluorination is disclosed. Only a catalytic amount of fluoride source is required to initiate the desilylation and afford -difluoroalkenes in very good to quantitative yields, using mild reaction conditions in dimethyl carbonate as a green solvent. This reaction uses (1-aryl)-2,2,2-trifluoroethyl-silanes, which are easily prepared via the insertion reaction of trifluoroethyl diazo alkanes into the Si-H bond of tertiary organosilanes.

Photochemical Cyclopropenation of Alkynes with Diazirines as Carbene Precursors in Continuous Flow.

An efficient synthesis of 3-trifluoromethyl-3-aryl-cyclopropenes via the cyclopropenation reaction of alkynes with photolytically generated carbenes from diazirine compounds is described. This reaction is performed in continuous flow using readily available LEDs under mild reaction conditions. This new and efficient method describes the synthesis of 25 examples of 3-trifluoromethyl-3-aryl-cyclopropenes with yields 97%, achieved in continuous flow with a 5 min residence time.

Asymmetric Cu-Catalyzed Insertion Reaction of 1-Aryl-2,2,2-trifluoro-1-diazoethanes into Si-H Bonds.

An asymmetric copper(I)-catalyzed Si-H insertion reaction of 1-aryl-2,2,2-trifluoro-1-diazoethanes in dimethyl carbonate as a green solvent alternative was developed. A -symmetric copper(I) diimine complex enabled the asymmetric insertion reaction to give enantioenriched (1-aryl-2,2,2-trifluoroethyl)silanes with excellent stereoselectivities (up to 98:2 ). Successful conversion of the silanes into the corresponding alcohols was performed with retention of stereochemistry.

α-Thiocarbonyl synthesis via the Fe-catalyzed insertion reaction of α-diazocarbonyls into S-H bonds.

Fe(OTf)2 was used to catalyze the insertion reaction of α-diazocarbonyls into S-H bonds at 40 °C. A wide range of α-thioesters were obtained in yields up to 96% within 24-48 h from their corresponding α-diazoesters. A variety of thiols were used for the unprecedented insertion reaction with an α-diazoketone, leading to yields up to 85% of α-thioketones.

Asymmetric Diels-Alder Reaction of α,β-Unsaturated Oxazolidin-2-one Derivatives Catalyzed by a Chiral Fe(III)-Bipyridine Diol Complex.

An asymmetric Fe-bipyridine diol catalyzed Diels-Alder reaction of α,β-unsaturated oxazolidin-2-ones has been developed. Among various Fe/Fe salts, Fe(ClO)·6HO was selected as the Lewis acid of choice. The use of a low catalyst loading (2 mol % of Fe(ClO)·6HO and 2.

Recent progress in the catalytic carbene insertion reactions into the silicon-hydrogen bond.

The following review will explore the historical development of Si-H bond insertion reactions, giving an up-to-date account on the metal catalysts often employed, in addition to an assessment of their strengths and weaknesses. Diazo compounds have great synthetic potential as versatile reagents for the formation of metal carbenes, allowing the selective formation of C-C and C-heteroatom bonds and thus the introduction of functional groups into organic molecules. C-Si bond-forming methods, that introduce silicon motifs into organic molecules, rely on catalysts derived from metals such as rhodium, copper, iridium, silver, ruthenium, and iron to achieve the desired activities and selectivities.

Synthesis of Aryl(2,4,6-trimethoxyphenyl)iodonium Trifluoroacetate Salts.

The direct synthesis of aryl(2,4,6-trimethoxyphenyl)iodonium trifluoroacetate salts from aryl iodides is described. Stoichiometric quantities of trifluoroacetic acid and trimethoxybenzene are used as the counteranion and auxiliary precursors, respectively, under oxidizing conditions. The reaction occurs at mild temperature, is broad in scope, and does not require a separate anion exchange step to install the trifluoroacetate group.