Synthetic studies towards crinipellins: construction of the functionalised C<SUB>20</SUB>-tetraquinane carbon framework through cationic enone-olefin cyclisation stratagem

A synthesis of 14-epi-crinipellin skeleton, adequately and appropriately functionalised, from a readily available triquinane precursor is described. In an approach to crinipellin A 1 , properly funtionalised C20-tetraquinane 21 has been synthesised from the readily available enone acetal 6