S. Hikichi et al., EFFICIENT AND PRACTICAL SYNTHESIS OF OPTICALLY-ACTIVE 5-T-BUTYLDIMETHYLSILOXY-2-CYCLOHEXENONE AS A CONVENIENT CHIRAL 2,5-CYCLOHEXADIENONE SYNTHON, Tetrahedron letters, 38(48), 1997, pp. 8299-8302
An efficient and practical method for the preparation of optically act
ive 5-t-butyldimethylsiloxy-2-cyclohexenone (3), a convenient chiral 2
,5-cyclohexadienone synthon, from readily available ethyl 4-chloro-3-h
ydroxy-butyrate (7) has been developed where Ti(II)-mediated intramole
cular nucleophilic acyl substitution and FeCl3-mediated ring expansion
are the key reactions. The synthesis of racemic 6-t-butyldimethylsilo
xy-2-cycloheptenone (10), a potential 2,6-cycloheptadienone synthon, i
s also described. (C) 1997 Elsevier Science Ltd.