| 摘要 |
<p>The present invention provides compounds of the general formula (I) <CHEM> in which R1 represents a hydrogen atom or a hydroxyl protecting group; R2 represents a hydrogen atom, or a trialkylsilyl group; A represents the group (CH2)qB(CH2)p wherein B represents oxygen (O), NH or a substituted or protected derivative thereof, or S(O)n wherein n is zero 1, or 2; q is zero or an integer from 1 to 4; p is zero or an integer from 1 to 4; with the proviso that the sum of p + q is an integer from 1 to 4; or B represents a bond and the sum of p + q is 2, 4 or 5; and -X-Y represents the alkene group (II) or the epoxide group (III). <CHEM> wherein R3 represents a C1-6alkyl group optionally substituted by halogen or an optionally substituted phenyl group; and processes for their preparation.</p> |
