ISSN:
0268-2605
Keywords:
regiospecific lithiation
;
2-furoic acid
;
5-ethyl-2-furoic acid
;
butyl-lithium
;
lithium di-isopropylamide (LDA)
;
furonaphthoquinone
;
Chemistry
;
Industrial Chemistry and Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Treatment of 5-ethyl-2-furoic acid with n-butyl-lithium in tetrahydrofuran gave regiospecific C-3 lithiation, whereas treatment of the same acid with lithium di-isopropylamide (LDA) afforded only starting material. The synthetic utility of dilithiated 5-ethyl-2-furoic acid has been demonstrated with the synthesis of two substituted 3-benzyl-5-ethyl-2-furoic acid derivatives which are key intermediates for the preparation of naturally occurring cytotoxic 2-ethylfuronaphthoquinones. Reaction of the C-3 lithiated species with two equivalents of benzaldehyde and subsequent reduction affored the corresponding 3-benzyl-5-ethyl-2-furoic acids. An alternative route to 5-ethyl-2-furoic acid has been described allowing for a more convenient preparation of longer-chain 5-alkyl-2-furoic acids.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
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