J. Wolfling et al., SYNTHESIS OF AZASTEROIDS AND D-HOMOSTEROIDS BY INTRAMOLECULAR CYCLIZATION REACTIONS OF STEROID ARYLIMINES, Synlett, (11), 1998, pp. 1205
Intramolecular Lewis acid-catalyzed cyclization reactions of steroid a
ryliminium salts 4a-e obtained from the secoestrone aldehyde 2 yield e
ither the tetrahydroquinoline derivatives of estrone methyl ether 8a-d
or the N-arylamino-D-homosteroids 7a-f, depending on the nature of th
e substituent R at the aniline moiety in 4.