ENANTIOSPECIFIC SYNTHESIS OF 4-(4'-METHOXYPHENYL)-HEXAN-3-ONE AS PRECURSOR FOR OPTICALLY-ACTIVE (PS) OR (PR) ISOMER OF (Z) OR )METHYLFERROCENYL)-4-(4''-METHOXYPHENYL)-HEX-3-ENE

We describe herein an original method for the preparation of enantiome rically pure (Z)- or )-3-(2'-((N,N-dimethylamino)methylferrocenyl)-4-( 4 ''-methoxyphenyl)-hex-3-ene possessing a p(S) or p(R) plane of chira lity. The key step of the synthesis lies in obtaining enantiomerically pure (R) or (S) 4-(4'-methoxyphenyl)-hexan-3-one whose reaction with the lithiated N,N-dimethylaminomethylferrocene leads to two enantiomer ically pure amino-alcohol diastereomers (pS,3S,4R) and (pR,3S,4R), or (pS,3R,4S) and (pR,3R,4S) respectively. Subsequent dehydration yields a mixture of three olefins, namely, two trisubstituted olefins and eit her the (Z)- or (E)-tetrasubstituted olefin with respect to the starti ng amino-alcohol diastereomer. Additionally we obtained the enantiomer ically pure (R)- and (S)-4-phenyl-hexan-3-one and the corresponding di astereomeric amino-alcohols. (C) 1998 Elsevier Science Ltd. All rights reserved.