The aldol condensation of the ketone 6 and the aldehyde 7 followed by an annelation-fragmentation afforded the bicyclo[6.4.0]dodecane derivative 3 with the appropriate functionalities for further elaboration.
A chemoenzymatic approach to the taxoid BC-substructure
The synthesis of a homochiral taxoid BC-unit containing the required functionalities on the B-ring periphery and a conveniently functionalized C-ring moiety by combination of enzymatic hydrolysis and the aldol-annelation-fragmentation sequence is described.