A formal synthesis of the C1-C9 fragment of amphidinolide C employing the Tamaru reaction.

Homoallylation of aldehydes with isoprene and triethylborane catalyzed by Ni(acac)(2) gave hydroxyalkenes in good yield with excellent regio- and stereoselectivity. Cross metathesis of the hydroxyalkenes with methyl acrylate using second-generation Grubbs catalyst and copper(I) iodide afforded alpha,beta-unsaturated esters, which underwent cyclization in the presence of DBU to produce tetrahydrofurans with the correct relative configuration for the C1-C9 fragment of amphidinolides C, C2, and F.