Direct Deprotonative Functionalization of α,α-Difluoromethyl Ketones using a Catalytic Organosuperbase

The deprotonative functionalization of α,α-difluoromethyl ketones is described herein. Using a catalytic organosuperbase and a silane additive, the corresponding difluoroenolate could be generated and trapped with aldehydes to deliver various α,α-difluoro-β-hydroxy ketones in high yields. This new strategy tolerates numerous functional groups and represents the access to the difluoroenolate by direct deprotonation of the difluoromethyl unit. The diastereoselective version of the reaction was also investigated with d.r. up to 93 : 7. Several transformations were performed to demonstrate the synthetic potential of these α,α-difluoro-β-hydroxy ketones. In addition, this method has been extended to the use of other electrophiles such as imines and chalcogen derivatives, and a difluoromethyl sulfoxide as nucleophile, thus leading to a diversity of difluoromethylene compounds.

Indium-Mediated Reformatsky Reaction of Iododifluoro Ketones with Aldehydes: Preparation of α,α-Difluoro-β-hydroxyketone Derivatives in Water

Indium can efficiently mediate the Reformatsky reaction of iododifluoroacetylketones with aldehydes to afford the corresponding α,α-difluoro-β-hydroxyketones in high yield in pure water This reaction has excellent substrate suitability and functional group selectivity and provides an efficient approach for the synthesis of bioactive molecules containing the α,α-difluoro-β-hydroxyketone pharmacophore.

Synthesis of 2,2-Difluoro-3-hydroxy-1,4-diketones via an HFIP-Catalyzed Mukaiyama Aldol Reaction of Glyoxal Monohydrates with Difluoroenoxysilanes

A novel efficient HFIP-catalyzed synthesis of structurally diverse 2,2-difluoro-3-hydroxy-1,4-diketone derivatives from readily available glyoxal monohydrates and difluoroenoxysilanes is described. This convenient protocol is induced by the distinctive fluorine effect of the reactants and the fluoroalcohol catalyst, which represents the first application of fluoroalcohol catalysis in a Mukaiyama aldol reaction.

Recent advances in C-F bond activation of trifluoromethylated carbonyl compounds and derivatives

The selective activation of the inert C-F bonds is one of the most challenging topics in modern organic chemistry. Trifluoromethylketones represent a class of versatile building blocks, which are inexpensive...

Copper-mediated cascade radical cyclization of olefins with naphthalenyl iododifluoromethyl ketones

Copper-mediated radical cyclization of naphthalenyl iododifluoromethyl ketones with olefins was developed to generate a series of unprecedented gem-difluorodihydrophenanthrenones with excellent regioselectivity.

Chemistry of detrifluoroacetylativelyin situgenerated fluoro-enolates

This review article provides a summary of the detrifluoroacetylativein situgeneration of fluorine-containing enolates and their related reactions.

Switching Chemoselectivity: Using Mechanochemistry to Alter Reaction Kinetics

A reaction manifold has been discovered in which the chemoselectivity can be altered by switching between neat milling and liquid assisted grinding (LAG) with polar additives. After investigation of the reaction mechanism, it has been established that this switching in reaction pathway is due to the neat mechanochemical conditions exhibiting different kinetics for a key step in the transformation. This proof of concept study demonstrates that mechanochemistry can be used to trap the kinetic product of a reaction. It is envisaged that, if this concept can be successfully applied to other transformations, novel synthetic processes could be discovered and known reaction pathways perturbed or diverted.

Decarboxylative aldol reaction of α,α-difluoro-β-ketocarboxylate salt: a facile method for generation of difluoroenolate

We developed a decarboxylative aldol reaction using α,α-difluoro-β-ketocarboxylate salt, carbonyl compounds, and ZnCl₂/N,N,N′,N′-tetramethylethylenediamine. The generation of difluoroenolate proceeded smoothly under mild heating to provide α,α-difluoro-β-hydroxy ketones in good to excellent yield (up to 99%). The α,α-difluoro-β-ketocarboxylate salt was bench stable and easy to handle under air, which realizes a convenient and environmentally friendly methodology for synthesis of difluoromethylene compounds.

A ZnCl₂/N,N,N′,N′-tetramethylethylenediamine complex promoted decarboxylative aldol reaction of α,α-difluoro-β-ketocarboxylate salt with carbonyl compounds has been developed.