Stereoselective construction of β-isopropenyl alcohol moiety at the C(2) and (3) of kallolide A and pinnatin A using a [2,3] wittig rearrangement of cyclic furfuryl ethers

A stereocontrolled synthesis of anti- and syn-beta-isopropenyl alcohol moieties at the C(2)-C(3) positions of kallolide A and pinnatin A was accomplished employing the [2,3] Wittig rearrangement of (E)-and (Z)-cyclic furfuryl ethers 8. Enantioselective Wittig rearrangement of (E)- and (z)-furfuryl ethers 8 using butyllithium and a chiral bis-(oxazoline) was also examined to provide (2R,3R)-homoallylic alcohol anti-9 in up to 61% ee and (2R,3S)-syn-9 in up to 93% ee, respectively.