[reaction: see text] An efficientsynthesis of the tricyclic A-B subunit 2 of angelmicin B is described. A formal three-component coupling of aldehydes 4 and 6 with gamma-silylallylborane 7 was employed to assemble the tetrahydrofuranyl core of 2, a strategy highlighted by the stereoselective [3 + 2] annulation of allylsilanes 5a/5b with aldehyde 4. The efficiency of the [3 + 2] annulation was greatly improved