Preparation and Transformation of Chiral 1,2-Disubstituted Ferrocenes:The Chiral Ferrocene with a Stronger Arm

摘要

Several new optically active 1,2-disubsituted ferrocenes were prepared from ortho-aminobenzyl substituted formyl ferrocene 1.The amino alcohol 2 was converted into the 1,4-diacetate 3a on treatment with acetic anhydride with retention of configuration.On treatment of 3a with aqueous ammonium in THF/MeOH gave the single diastereomer of the 1,2-acetoamido alcohol 8a with retention of configuration.Thus the ferrocenyl diacetate 3 has a "stronger arm",one side of the acetoxy group being selectively displaced by ammonia.The reaction mechanism of formation of a single isomer of acetoamido alcohol 8 will be discussed.