US EPA

7857159 

Journal Article 

The stereospecific Barbier reaction between (Z)- and (E)-1-iodopentafluoropropenes, zinc and aldehydes - Mechanistic aspects and scope of the preparation of (Z)- and (E)-partially fluorinated allylic alcohols 

Jairaj, V; Burton, DJ 

2001 

Yes 

Journal of Fluorine Chemistry
ISSN: 0022-1139
EISSN: 1873-3328 

ELSEVIER SCIENCE SA 

LAUSANNE 

111 

2 

233-240 

English 

10.1016/S0022-1139(01)00460-2 

WOS:000171759900020 

The Zn/Barbier reaction of acid-washed zinc or zinc/silver couple with (Z)- or (E)-CF3CF=CFI and aromatic aldehydes in DMF stereospecifically gives the (Z)- or (E)-allylic alcohol, CF3CF=CFCH(OH)C6H5. Substituted aromatic aldehydes, which contain an electron-withdrawing group, undergo Barbier addition reaction. Substituted aromatic aldehydes, which contain an electron-releasing group, fail to undergo Barbier addition reaction. Aliphatic aldehydes, such as butanal, which contain an α-H, fail to undergo Barbier addition and significant amounts of CF3CF=CFH are formed. When the addition reaction is carried out in the presence of 1,4-dinitrobenzene, no reaction is observed. Mechanistically, the Zn/Barbier addition of CF3CF=CFI to aromatic aldehydes is best explained by formation of the [CF3CF=CF]⊖ anion which adds to the aldehyde and is not adequately explained by formation and addition of an unsolvated zinc reagent, CF3CF=CFZnI (unsolvated). © 2001 Elsevier Science B.V. All rights reserved. 

Barbier reaction; vinylzinc reagents; fluorinated allylic alcohols; stereospecific reactions