In fluorous triphasic reactions, such as bromination of alkenes by dibromine and dealkylation of aromatic ethers by boron tribromide, the middle fluorous phase acts as a liquid membrane permitting passive transport of the reagents at the bottom to the top layer involving the substrates, thereby regulating the reactions.
Cascade reactions of 4-alkenyl iodides, involving a carbonylation−cyclization−carbonylation sequence, were accomplished by a hν/Pd system. The stereochemical outcomes suggest that radical carbonylation and subsequent acyl radical cyclization may be involved in this reaction.
Molecular orbital calculations predict that the 5-azahexenoyl radical ring closes via nucleophilic addition to the acyl carbon to afford the 5-exo product; CCSD(T)/cc-pVDZ//BHLYP/cc-pVDZ calculations predict energy barriers of 36.1 and 46.9 kJ mol–1 for the exo and endo cyclization modes of the 5-azahexenoyl radical, respectively.
The PdCl2(PPh3)2-catalyzed Sonogashira coupling reaction, in good to high yields, was performed in an ionic liquid ([BMIm][PF6]) in the absence of a copper salt. The use of an ionic liquid allows for the facile separation and recycling of the catalyst. The application of the above reaction in a microflow system in conjunction with an IMM micromixer was also successful.
A new fluorous/organic amphiphilic ether solvent, 1H,1H,2H,2H-perfluorooctyl 1,3-dimethylbutyl ether (F-626), is introduced. The basic properties of F-626, especially the partition coefficients with organic solvents/FC-72 (perfluorohexane), were investigated. F-626 was easy to remove by fluorous biphase treatment. Using F-626 as a solvent, LAH reduction, catalytic hydrogenation, and fluorous reductive radical reactions were successful. Classical high temperature reactions up to 200°C, such as the Vilsmeier formylation, the Wolff–Kishner reduction, and the Diels–Alder reaction, were also examined in F-626. The yields of the products in F-626 were almost comparable with those conducted in common organic solvents, which prove that F-626 has the potential to be an easily recyclable high boiling solvent.
The cross-coupling reaction of dianion cuprates, generated from ketone α,β-dianions and copper salts, with acid chlorides, was studied. The reaction gave good to moderate yields of unsymmetrical 1,4-diketones. The consecutive treatment of a dianion cuprate with cyclohexanecarbonyl chloride and methyl iodide or two different acid chlorides gave 2-methyl-substituted 1,4-diketone or triketone, respectively.