Bicyclo[3.4.0]non-1-en-derivate. synthese von des-a-pregn-9-en-3,20-dion
作者:E.-J. Brunke、H. Bielstein、R. Kutschan、G. Rehme、H.-J. Schuetz、H. Wolf
DOI:10.1016/0040-4020(79)80023-x
日期:1979.1
Cyclization of the allylic alcohols 12,17 and 22 easily obtainable from Hagemann's ester (2 or 1) via the cyclohexenone derivatives 7 and 10 was investigated with regard to steroid syntheses of the pregnane series. The 6,7-cis-tetrahydroindane derivatives 16a and 23 are formed stereoselectively by acid catalyzed cyclization of 12 or 22; ringclosure of 22 occurs largely regioselectively. Cyclization