A Convenient Method of Polyfluoroalkyl—lactonization

A novel synthesis of polyfluoroalkyl substituted γ-butyrolacones from the reaction of polyfluoroalkyl iodides with 4-pentenoic acid initiated with sodium dithionite was realized in good yields.     

Synthesis of 5,6-dihydro-2H-thiins and 2,3-dihydro-1,4-oxathiins based on 1-benzylsulfonyl-1,1-dihydropolyfluoroalkan-2-ones

1-Benzylsulfonyl-1,1-dihydropolyfluoroalkan-2-ones react with phthalimidosulfenyl chloride or succinimidosulfenyl chloride to form the sulfenylated products on the active methylene group, 1-benzylsulfonyl-1-phthalimido(succinimido)thiopolyfluoroalkan-2-ones. Decomposition of the latter leads to formation of 1-benzylsulfonyl-1-thioxopolyfluoroalkan-2-ones. These compounds easily undergo the hetero Diels-Alder reaction with electron-rich 1,3-dienes as dienophiles and with electron-rich olefins as hetero-1,3-dienes. Polyfluoroalkyl substituted derivatives of six-membered sulfur-containing heterocycles, 5,6-dihydro-2H-thiins and 2,3-dihydro-1,4-oxathiins, are obtained as a result of these reactions.     

A convenient synthesis of fluoroalkylated γ-butyrolactones from polyfluoroalkyl iodides and 4-pentenoic acid catalyzed by Pd(PPh3)4

A convenient synthesis of fluoroalkylated γ-butyrolactones was realized through the reaction of fluoroalkyl iodides with 4-pentenoic acid in the presence of catalytic amounts of tetrakis(triphenylphosphine)palladium and sequential treatment with triethylamine in 79-85% yields.     

Electrophilic polyfluoroalkylating agents based on sulfonate esters

This review surveys selected electrophilic polyfluoroalkylating reagents, polyfluoroalkyl alkane- and arenesulfonates, that have been used for the introduction of longer perfluorinated chains (C_nF_2n+1; n ≥ 4) with methylene, ethylene or propylene spacers into the substrate. Polyfluoroalkyl mesylates, tosylates, triflates and nonaflates are described with their applications in various syntheses of polyfluorinated compounds.     

2-Oxo-2-polyfluoroalkylethane-1-sulfones and -sulfamides in the Biginelli and ‘retro-Biginelli’ reactions

2-Oxo-2-polyfluoroalkylethane-1-sulfones and -sulfamides react with aryl aldehydes and urea under Biginelli reaction conditions to yield 4-hydroxy-4-polyfluoroalkyl-5-sulfonyl-6-aryl-tetrahydropyrimidinones. The latter compounds on reaction with hexamethylenetetramine (HMTA) under thermal conditions undergo ‘retro-Biginelli’ reaction involving replacement of the 6-aryl substituent of the pyrimidinone cycle with a hydrogen atom donated by HMTA. Hexamethylenetetramine was employed for the first time in place of formaldehyde in the reported one-step Biginelli protocol for the synthesis of fluorinated sulfonyl-containing 6-unsubstituted tetrahydropyrimidinones.     

Synthesis of fluoroalkyl-δ-lactones from polyfluoroalkyl iodides and 5-hexenoic acids

The polyfluoroalkyl-lactonization of 5-hexenoic acids with the polyfluoroalkyl iodides initiated by sodium dithionite was carried out in aqueous acetonitrile, providing an efficient method for the synthesis of fluorine-containing δ-valerolactones. Formation of R_fCH₂CHCH(CH₂)₂COOH appeared to be unexpected minor product in sulfinatodehalogenation reagents.