Stereocontrolled synthesis of lepadiformine A.

In this paper we present results of a study into whether the tricyclic core of the lepadiformines A-C can be accessed via intramolecular hetero-Diels-Alder cycloaddition. We are able to demonstrate that such a process is possible and that the reaction proceeds in an endo-selective fashion, providing the correct relative stereochemistry for this family of natural products. By employing this approach we have been able to develop a short (7 step) synthesis of (+/-)-lepadiformine A, starting from commercially-available trans-2-nonenal.

Deprotonation-electrophile trapping of terminal epoxides.

Organolithium-induced deprotonation of terminal epoxides in the presence of appropriate diamine ligands allows trapping with a range of electrophiles, yielding functionalised di- and tri-substituted epoxides in good yields and with control of stereochemistry at the epoxide.

Enantioselective synthesis of epoxides by alpha-deprotonation--electrophile trapping of achiral epoxides.

Enantioselective alpha-deprotonation of achiral epoxides 1, 21, and 26 using organolithiums in the presence of (-)-sparteine 2 and subsequent electrophile trapping gives access to enantioenriched trisubstituted epoxides 9-17, 22, 23, 27 and 28 (in up to 86% ee).