First Highly Efficient Asymmetric Synthesis of the Hyrtios Erectus Diketotriterpenoid

Abstract

The first highly efficient asymmetric synthesis of the diketotriterpenoid 1, isolated from the Indonesian marine sponge Hyrtios erectus, in good overall yield and employing simple starting materials such as butanone, is described. Both stereogenic centres at the C-6 and C-19 positions of the C ₂-symmetrical molecule were generated via α-alkylation employing the SAMP/RAMP hydrazone method with high asymmetric inductions (de, ee ≥ 96%). The absolute configuration of the natural material was determined as R,R.

Key words

asymmetric synthesis - hydrazones - alkylations - natural products - terpenoids

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