Preparation of cis-5-methoxy-and-7-methoxy-1-acetoxy-1,2,3,4,4a,10a- hexahydro-9(10H)-phenanthrenone. An epoxide-arene reaction involving a selective 1,2-alkyl shift rearrangement

Article abstract of DOI:10.1016/S0040-4020(96)00927-1

The preparation of cis-1α-acetoxy-7-methoxy-1,2,3,4,4a,10a-hexahydro-9(10H)-phenanthrenone 5 was accomplished starting from 6-methoxy-1-tetralone. Reduction of 7-methoxy-1,2,3, 4,9,10-hexahydro-1-oxo-phenanthrene 8, acetylation and subsequent oxidation delivered 5, Application of an analogus procedure to the preparation of cis-1β-acetoxy-5-methoxy-1,2,3,4,4a,10a-hexahydro-9(10H)-phenanthrenone 6 was not feasible. A more elaborate route was developed for the synthesis of compound 6, where an epoxide-arene reaction involving a 1,2-alkyl shift rearrangement, constituted a highly selective key transformation.