Regio- and stereoselective a4-umpolung reactions of α,β-unsaturated esters to 1,6-dicarbonyl compounds by addition of enantiopure nucleophiles to racemic tetracarbonyl (η3-alyl)iron(1+) complexes

Abstract The nucleophilic addition of various enantiopure d 2 -carbon nucleophiles (chiral enamines 1 or metalated imines 2 and silylketon derivatives 3 ) to racemic planar chiral electrophilic tetracarbonyl( η 3 -allyl)iron(1+) complexes 5 proceeds with complete γ-radioselectivity and with kinetic resolution of complex 5 . Subsequent oxidative demetalation provides access to enantiometrically enriched ( ee 92%) 1,6-dicarbonyl compounds 7 in moderate overall yields (14–53%, four steps or 5–21%, five steps) and with retention of The ( E -double bond geometry with respect to the starting material 4.