| abstract |
A compound has formula (1) in racemic form, enantiomerically enriched form or enantiomerically pure form. R6 is preferably -Si(R8R9R1O) or -(R?7)Si(R8R9R10¿), wherein R7 is an alkylene group, an alkenylene group, or an alkynylene group; and R?8, R9 and R10¿ are independently a C¿1-10? alkyl group, a C?2-10¿ alkenyl group, a C2-10 alkynyl group, an aryl group or a -(CH¿2)NR?11 group, wherein N is an integer within the range of 1 through 10 and R11 is a hydroxy group, alkoxy group, an amino group, an alkylamino group, a dialkylamino group, a halogen atom, a cyano group, -SRc or a nitro group. R1-R4 can be broadly substituted. R5 is preferably a C¿1-10? alkyl group, an alkenyl group, an alkynyl group, or a benzyl group. R?13¿ is preferably H, F or -CH¿3. R?16 is -C(O)Rf or H. The E-ring (the lactone ring) may be opened. A method of synthesis of compound (1) and intermediates in the synthesis thereof are provided. |