Synthesis of Spiro[4.5]decan-1-ones: A Formal Synthesis of Acoradienes and Related Sesquiterpenes via Rhodium-catalyzed Claisen Rearrangement/Hydroacylation

Abstract

A novel procedure for the synthesis of spiro[4.5]decan-1-ones starting from commercially available substances is described. The key-step is a one-pot combination of Claisen rearrangement of allyl vinyl ethers followed by an intramolecular hydroacylation1 catalysed by RhCl(cod)(dppe).2 The intermediate pent-4-enals generated by the initial [3.3] sigmatropic rearrangement exhibit substitution patterns which have previously been described as unsuitable for the rhodium catalysed intramolecular hydroacylation.3,4 This procedure allows the synthesis of ketone 2, a key intermediate in the total synthesis of acoradienes and acorones.5