Towards the Synthesis of Paulitin: New Insights into the Enyne-Metathesis Mechanism

Abstract

In our approach towards Paulitin, a sesquiterpene lactone, we have shown that steric hindrance at the propargylic position is of importance to the outcome of enyne metathesis. Moreover, we have uncovered further evidence to confirm that the alkyne-first pathway should be the favored process in enyne metathesis.

Key words

metathesis - alkyne - steric hindrance - 1,3-dienes - ­mechanism

References

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• 8a

  This could be done in a one-step procedure according to our previous work (see ref. 8b) or in a two-step procedure (see ref. 8c).

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7

According to NMR spectra, regioisomer 2 seemed to be isolated as one single stereoisomer whose configuration was not determined.