text: Carbonyl allylation has been employed in the synthesis of polyketide natural products and other oxygenated molecules with a contiguous array of stereocenters.  For example, allylstannanation of a threose-derived aldehyde affords the macrolide antascomicin B, which structurally resembles FK506 and rapamycin, and is a potent binder of FKBP12. The Krische allylation was used to prepare the polyketide (+)-SCH 351448, a macrodiolide ionophore bearing 14 stereogenic centers.