3 Cyclisation of 5 using 1.1 equiv of carbonyldiimidazole in THF afforded the target acylpyrone skeleton 7. Reduction of the a-acyl group in 7 utilising NaCNBH3 in THF/aq HCl24 afforded pseudopyronine A
3 Cyclisation of 5 using 1.1 equiv of carbonyldiimidazolein THF afforded the target acylpyrone skeleton 7.Reduction of the a-acyl group in 7 utilising NaCNBH3 inTHF/aq HCl24 afforded pseudopyronine A