Involved in the conversion of (2S)-naringenin to (+)-(2R/3R)-dihydrokaempferol. 2-oxoglutarate + a (2S)-flavan-4-one + O2 = a (2R,3R)-dihydroflavonol + CO2 + succinate Binds 1 Fe(2+) ion per subunit. Secondary metabolite biosynthesis; flavonoid biosynthesis. Belongs to the iron/ascorbate-dependent oxidoreductase family.