Stereocontrolled (Me₃Si)₃SiH-Mediated Radical and Ionic Hydride Transfer in Synthesis of 2,3,5-Trisubstituted THF

2,3,5-Trisubstituted tetrahydrofurans were prepared stereoselectively through a two-step process involving the addition of an acyl radical to a β-silyloxy acrylic ester followed by an acid-catalyzed desilylation–ketalization sequence and a final oxocarbenium reduction step. High levels of 1,2- and 1,3-stereocontrol were attained when (Me3Si)3SiH was used as a radical followed by a ionic hydrogen transfer agent.