(E)-4-[(2R,4R)-2-((R)-2-Hydroxy-1-methyl-ethyl)-6-oxo-tetrahydro-pyran-4-yl]-but-2-enoic acid tert-butyl ester

[4R,6R,6(1R)]-4-allyl-6-[(1-methyl-2-hydroxy)ethyl]-4H-pyran-2-one