New results in the total synthesis of 19-norsteroids

Recent endeavors in the field of steroid total synthesis have led to several new approaches which utilize the principle of asymmetric induction. Important developments will briefly be reviewed, followed by a presentation of two novel routes to estrone. The first is based on the use of (—)-(5S)-5-hydroxy-9-oxodecanoic acid lactone which is transformed in several steps to d-(−)-estra-4.9-diene-3, 17-dione and thence to estrone. The second, altogether different route starts with (+)-(7aS)-7,7a-dihydro7a-methyl-1,5(6H)-indandione and involves the preparation of a 9,10- seco ACD-tricyclic intermediate and its conversion into d-(+)-estrone methyl ether.