Equilenin, also known as 6,8-didehydroestrone, as well as estra-1,3,5(10),6,8-pentaen-3-ol-17-one, is a natural product, naturally occurring steroidal estrogen (medication), estrogen obtained from the urine of pregnancy, pregnant mares. It is used as one of the components in conjugated estrogens (brand name Premarin). It was the first complex natural product to be fully synthesized, in work reported by 1940 by Werner Emmanuel Bachmann, Bachmann and Alfred L. Wilds, Wilds.

Chemistry

Synthesis

Total synthesis

The synthesis developed by the Werner Emmanuel Bachmann, Bachmann group started from Butenand's ketone – the 7-methoxy structural analog of 1,2,3,4-tetrahydrophenanthren-1-one – and which can be readily prepared from 1,6-Cleve's acid. The approach was based on well-established transformations like the Claisen condensation, the Reformatsky reaction, the Arndt–Eistert reaction, and the Dieckmann condensation. K. C. Nicolaou, Nicolaou described this preparation as ending the era preceding the post-World War II work of Robert Burns Woodward that introduced enantioselective synthesis; in this synthesis, a mixture of stereoisomers were prepared and then chiral resolution, resolved, and the choice of target was partly because of the existence of only two chiral carbons and hence only four stereoisomers. The overall yield of the synthesis was 2.7% based on a twenty-step process starting from Cleve's acid.

References

{{Estrogen receptor modulators Sterols Phenols Estranes Estrogens Ketones

Chemistry

Synthesis

Total synthesis

See also

References