Tetrahydrofuran → 21-methylene-20(R)-methylpregn-4-en-3-one

Beteiligte Stoffe

Reaktionsschritte

These syntheses are depicted in FIG. 178. Androsta-4,16-dien-3-one (4) was reduced at -55° with 5 lithium tris (1, 2-dimethylpropyl) hydridoborate in THF (c) as described for the preparation of 2 (FIG. 1). Chromatography on silica gel with CH2Cl2 /ethyl acetate 9:1 gave pure axial alcohol 5 (48% yield) and pure equatorial alcohol 6 (48% yield). Analytical samples were further purified by recrystallization (from PE at -30° for 5, from cyclohexane at RT. for 6).

Herkunft & Nachweise