New strategy for the construction of a monotetrahydrofuran ring in Annonaceous acetogenin based on a ruthenium ring-closing metathesis: application to the synthesis of Solamin.

An original convergent total synthesis of Solamin (type A annonaceous acetogenin) was achieved. The central THF core was obtained by means of a ring-closing metathesis (RCM) reaction using a ruthenium imidazolylidene complex. The RCM substrate was prepared from a vinyl-substituted epoxide by reaction with an allyl alcohol, both synthesized from propargylic alcohol. The flexibility of the strategy should be useful in preparing various natural and unnatural annonaceous acetogenins.
(Copyright 2004 American Chemical Society)