Asymmetric synthesis of a branched-chain analogue of azapyranoses from a 5-allylic derivative of 5-nitro-1,3-dioxane. Synthesis of (3R,4S)-6,6-bis(hydroxymethyl)-3,4-dihydroxypiperidin-2-one

Methyl 4-(5-nitro-1,3-dioxaspiro[5.5]undecan-5-yl)but-2-enoate 2, obtained from the palladium(0)-catalyzed reaction of a salt of 5-nitro-1,3-dioxane 1 with methyl γ-bromocrotonate, was converted into the title piperidinone (ee 78%) in three steps.