A new fluorous/organic amphiphilic ether solvent, F-626: execution of fluorous and high temperature classical reactions with convenient biphase workup to separate product from high boiling solvent

Radical hydroxymethylation of alkyl iodides using formaldehyde as a C1 synthon

Radical hydroxymethylation using formaldehyde as a C1 synthon is challenging due to the reversible and endothermic nature of the addition process. Here we report a strategy that couples alkyl iodide building blocks with formaldehyde through the use of photocatalysis and a phosphine additive. Halogen-atom transfer (XAT) from α-aminoalkyl radicals is leveraged to convert the iodide into the corresponding open-shell species, while its following addition to formaldehyde is rendered irreversible by trapping the transient O-radical with PPh₃. This event delivers a phosphoranyl radical that re-generates the alkyl radical and provides the hydroxymethylated product.

Halogen-atom transfer (XAT) based on phosphoranyl radical chemistry enables the hydroxymethylation of alkyl iodides with formaldehyde.

Phosphorus-Recycling Wittig Reaction: Design and Facile Synthesis of a Fluorous Phosphine and Its Reusable Process in the Wittig Reaction

This study shows that phosphorus sources can be recycled using the appropriate fluorous phosphine in the Wittig reaction. The designed fluorous phosphine, which has an ethylene spacer between its phosphorus atom and the perfluoroalkyl group, was synthesized from air-stable phosphine reagents. The synthesized phosphine can be used for the Wittig reaction process to obtain various alkenes in adequate yields and stereoselectivity. The concomitantly formed fluorous phosphine oxide was extracted from the reaction mixture using a fluorous biphasic system. The fluorous phosphine was regenerated by reducing the fluorous phosphine oxide with diisobutylaluminum hydride. Finally, a series of gram scale phosphorus recycling processes were performed, which included the Wittig reaction, separation, reduction, and reuse.

Use of a "Catalytic" Cosolvent, N,N-Dimethyl Octanamide, Allows the Flow Synthesis of Imatinib with no Solvent Switch

A general, efficient method for C-N cross-coupling has been developed using N,N-dimethyloctanamide as a catalytic cosolvent for biphasic continuous-flow applications. The described method was used to generate a variety of biarylamines and was integrated into a two-step sequence which converted phenols into biarylamines via either triflates or tosylates. Additionally, the method was applied to a three-step synthesis of imatinib, the API of Gleevec, in good yield without the need of solvent switches.

One-pot synthesis of cyanohydrin derivatives from alkyl bromides via incorporation of two one-carbon components by consecutive radical/ionic reactions

The consecutive radical/ionic reaction consisting of radical formylation of alkyl bromides and nucleophilic addition of a cyanide ion was investigated, which gave moderate to good yields of cyanohydrin derivatives in one-pot.

Synthesis and properties of fluorous benzoquinones and their application in deprotection of silyl ethers

1,4-Benzoquinone derivatives bearing perfluoroalkyl groups were prepared and used as a recyclable catalyst in the selective desilylation of silyl ethers.

Radical reactions of borohydrides

This review article focuses on state-of-the-art borohydride based radical reactions, also covering earlier work, kinetics and some DFT calculations with respect to the hydrogen transfer mechanism.

A THEORETICAL STUDY OF THE INTERACTIONS OF IODO-PERFLUOROCARBON AND IODO-HYDROCARBON WITH HALOID ANIONS

Ab initio calculations have been performed on a series of complexes formed between iodo-perfluorocarbons(PFCs) and iodo-hydrocarbons(HCs) and haloid anions to gain a deeper insight into the nature of halogen bonds. It appears that halogen bonds in these complexes are much stronger than neutral halogen bonds. Calculations also show that the strength of halogen bonds in iodo-PFC⋯ haloid anion dimers are greater than those in iodo-HC⋯ haloid anion dimers. A comparison of the two complex series reveals that the hybridization state of the carbon atom bonded to iodine has a less pronounced effect on the interatomic distances I⋯X in the iodo-PFC series in relation to the iodo-HC series. PCM calculations used to investigate the solvent effect on halogen bonds unveil that, in the gas phase, fluorine anion prefers to form halogen-bonded complexes with respect to chloride, bromide, and iodine anions; however, the preference is not obvious, and even an opposite order is observed in solutions. It is worth mentioning that the iodo-PFC⋯ fluorine anion complexes present a special structure, i.e. the interatomic I⋯F distances in these complexes are relatively short and the corresponding C–I bonds tend to be further broken. These features, in combination with the geometrical data, indicate that ate-complexes are formed between iodo-PFC and fluorine anions.

Fluorous organic hybrid solvents for non-fluorous organic synthesis

The rapid progress in fluorous chemistry shed the light on the use of fluorous-organic hybrid solvents for fluorous reactions; however, these hybrid solvents also have good potentials as solvents for ordinary organic synthesis. This chapter will survey the state of the art of the fluorous organic hybrid solvents as green substitutes for traditional organic solvents.

Synthesis of deep-cavity fluorous calix[4]arenes as molecular recognition scaffolds

Several lower-rim perfluoroalkylated (fluorous) calix[4]arenes have been synthesized by O-alkylation of the parent calix[4]arene. The compounds are formed in the cone conformation. They are soluble in several fluorous solvents and show promise for use in sensing, selective extractions and other applications.

New fluorous/organic biphasic systems achieved by solvent tuning

Miscibility tests between sixty pairs of fluorous and organic solvents have been performed, and a number of biphasic systems based on hydrofluoroether solvents have been identified. Mutual solubilities of a series of fluorous and organic solvents have been measured to ascertain the compositions of the biphasic systems. A qualitative solvent tuning strategy based on solvent polarity and fluorophilicity/phobicity is introduced. Solvent tuning is then used to modulate the partition coefficients (P) of triarylphosphines with 0-3 fluorous tags. The results lay a foundation for future applications of these and related biphasic systems in catalysis and extraction.

Mizoroki−Heck Arylation of α,β-Unsaturated Acids with a Hybrid Fluorous Ether, F-626: Facile Filtrative Separation of Products and Efficient Recycling of a Reaction Medium Containing a Catalyst

The Mizoroki-Heck reaction was carried out using a fluorous ether F-626 as the solvent and a fluorous Pd carbene complex as the catalyst. When carboxylic acids are the products, separation of both the F-626 and the Pd catalyst from the products can be conveniently carried out by simple filtration. The F-626 filtrates containing the Pd catalyst can be recycled.

New approaches in radical carbonylation chemistry: fluorous applications and designed tandem processes by species-hybridization with anions and transition metal species

New approaches in radical carbonylation chemistry are described. We have successfully integrated tin mediated radical carbonylation chemistry into modern fluorous applications and separation techniques. We revealed that radical carbonylation reactions can be performed using fluorous tin mediators, such as fluorous tin hydride and fluorous allyltin reagents. Fine tuning of the reaction conditions resulted in a good efficiency equivalent to conventional tin mediators. The tedious procedure of removing organotin byproducts can be circumvented through the use of fluorous/organic liquid-liquid extraction or fluorous liquid-solid phase extraction with fluorous reverse phase silica (FRPS). Also described are newly developed tandem carbonylation reactions that are based on species hybridization approaches. Using a radical/anionic hybrid system based on zinc-induced one-electron reduction, we achieved a three-component coupling reaction consisting of 4-alkenyl iodides, carbon monoxide, and electron-deficient alkenes. We observed two types of annulations processes, namely [4 + 1](radical)/[3 + 2](anionic) and [5 + 1](radical)/[3 + 2](anionic), which lead to the production of bicyclo[3.3.0]octanols and bicyclo[3.2.1]octanols, respectively. We found a radical/palladium hybrid system to be useful in the construction of new cyclic systems that incorporate two or three molecules of carbon monoxide.