The Baylis-Hillman class of olefins undergoes a facile osmium-catalyzed aminohydroxylation reaction. The diastereoselectivity for the aminohydroxylation is influenced by the aldehyde-derived substituent, while the acrylate-derived substituent has a minimal effect. A variety of derivatives and close analogs of the Baylis-Hillman product-core failed to aminohydroxylate, emphasizing the unique reactivity of this class of olefins.