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Synlett 2010(4): 615-617  
DOI: 10.1055/s-0029-1219159
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Copper-Bisphosphine-Initiated Pentafluorophenylation of Aldehydes and Ketones

Samantha Brogana, Neil B. Carterb, Hon Wai Lam*a
a School of Chemistry, University of Edinburgh, The King’s Buildings, West Mains Road, Edinburgh, EH9 3JJ, UK
Fax: +44(131)6506453; e-Mail: h.lam@ed.ac.uk;
b Syngenta, Jealott’s Hill International Research Centre, Bracknell, Berkshire, RG42 6EY, UK
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Publikationsverlauf

Received 30 October 2009
Publikationsdatum:
22. Dezember 2009 (online)

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Abstract

In the presence of substoichiometric quantities of a ­copper-bisphosphine complex, a variety of aldehydes and reactive ketones undergo pentafluorophenylation using pentafluorophenyl­trimethylsilane.

Key words

aldehydes - copper - ketones - nucleophilic addition - pentafluorophenylation

18

Initial investigations employed benzaldehyde as a test substrate. The use of toluene instead of THF¹6 provided only minimal conversions (<5%). Decreasing the loadings of Cu(OAc)2 and dppe to 5 mol%, or replacement of Cu(OAc)2 with Cu(acac)2 ¹7 resulted in lower conversions.

19

For example, 2-furancarboxaldehyde and 1-methylindole-2-carboxaldehyde showed only low conversions (ca. 20% and <5%, respectively), while 2-pyridinecarboxaldehyde resulted in a complex mixture of products.