SYNTHESIS, X-RAY STRUCTURE AND CHEMICAL-PROPERTIES OF 17-ALPHA-FERROCENYLESTRADIOL

The X-ray structure of 17 alpha-ferrocenylestradiol 1a shows that the ferrocenyl group is at the alpha position of the steroid, below the plane of the D ring. From acidic medium it is possible to obtain and isolate the derivative with a carbenium ion in 17-alpha position. This ion is transformed by various nucleophiles into the corresponding olefin 3 with -C=C- at the C16-C17 position. With NaBH4 in acidic medium the reduction leads to a mixture of 17 alpha- and 17 beta-ferrocenyl C19H26O 4a, 4b with a predominance of the beta product, owing to a more favourable entrance of hydride in the alpha position. The oxidized derivative 17 alpha-ferriciniumyl-estradiol tetrafluoroborate 5 was prepared and its are properties described.