Stemodinone

The syntheses of stemodin and stemodinone, structural relatives of aphidicolin, were accomplished using the A/B double annulation and B/C spiro annulation processes developed for the assembly of aphidicolin. 

Boyd, J.W., Greaves, N., Kettle, J., Russell, A.T., and Steed, J.W. (2005) Alkene-Arene meta photocycloadditions with a four-carbon-atom tetheu efficient approach toward the polycyclic ring systems of aphidicolin and stemodinone. Angewandte Chemie, International Edition, 44, 944—946. 

Two different syntheses of aphidicolin (106) were reported in 1979. Corey and his co-workers have now completed a third.A key feature of their route is the base-induced conversion of (104) to (105). It was found that the desired alkylation occurred only under carefully controlled reaction conditions (lithium di-t-butylamide at —102 C), the alternative a-alkylation product predominating under most other conditions. A closely related approach has resulted in the synthesis of ( )-stemodin (107) and ( )-stemodinone (108). The Kametani route to the aphidocolanes has been described earlier in this chapter. 

Figure 6 Hydroxylation of stemodin 47 and stemodinone 48 by Cephalosporium aphidicola.

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