Stereocontrolled Total Synthesis of (+)-Altohyrtin A/Spongistatin 1 Financial support was provided by the EPSRC (GR/L41646), Cambridge Commonwealth Trust (Scholarship to M.J.C.), EC (Marie Curie Postdoctoral Fellowship to J.L.A.), DFG (Postdoctoral Fellowship to T.T.), NSERC-Canada (Postdoctoral Fellowship to R.M.O.), Churchill College (Research Fellowship to D.J.W.), Kingapos;s College and Sims Fund, Cambridge (Scholarship to D.Y.K.C.). We also thank Merck and AstraZeneca Pharmaceuticals for generous support, and Dr. Anne Butlin (AZ) and Dr. Nick Bampos (Cambridge) for valuable assistance.