INTERMEDIATES AND PREPARATION THEREOF FOR THE ENANTIOSELECTIVE SYNTHESIS OF (20R) HOMOCAMPTOTHECINS

摘要

A method of synthesizing a compound having the formula (V), from a compound having the formula (III), wherein R1 is hydrogen, fluorine, chlorine or SiR5R6R7, wherein R5, R6, and R7 are independently the same or different an alkyl group or an aryl group, R2 is an alkyl group, R3 is a protecting group, R4 is an alkyl group, an allyl group, a propargyl group -CO2H, or a benzyl group, R8 is -CO2R10, wherein R10 is an alkyl group or an aryl group, X1 is OH and X2 is H, includes the step of exposing compound (III) to at least one of an organic acid or an inorganic acid. A compound has the general formula (III).