An efficient synthesis of the potent phytoestrogens 8-prenylnaringenin and6-(1,1-dimethylallyl)naringenin by europium(III)-catalyzed Claisen rearrangement
S. Gester et al., An efficient synthesis of the potent phytoestrogens 8-prenylnaringenin and6-(1,1-dimethylallyl)naringenin by europium(III)-catalyzed Claisen rearrangement, TETRAHEDRON, 57(6), 2001, pp. 1015-1018
Starting from commercially available naringenin (3), the flavanoids 8-preny
lnaringenin (1) and 6-(1,1 -dimethylallyl)naringenin (2) have been prepared
in racemic form using prenyl ether 5 as a general intermediate. While a do
mino Claisen-Cope rearrangement of 5 was the key step in the synthesis of 1
, the cytotoxic compound 2 was additionally secured via a europium(III)-cat
alyzed Claisen rearrangement, of 5 at low temperature. Both 1 and 2 display
strong estrogenic activities. (C) 2001 Elsevier Science Ltd. All rights re
served.