A novel case of 1,3-asymmetric induction in rhodium-catalyzed hydroformylation of an allylic double bond using perbenzylated C-glucosides as chiral directors

1-(2′,3′,4′,6′-Tetra-O-benzyl-α-d-glucopyranosyl)-2-propene 1a and 1-(2′,3′,4′,6′-tetra-O-benzyl-β-d-glucopyranosyl)-2-propene 1b were hydroformylated at different temperatures affording linear and branched aldehydes in either a 1:1 or 2:1 regioisomeric ratio, depending on the stereochemistry of the starting substrate. The diastereoisomeric ratio of the branched isomer depended on the reaction temperature as well as the alkene structure, the highest value (85:15) being obtained in the case of hydroformylation of the α-isomer at 0 °C.

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1-(2′,3′,4′,6′-Tetra-O-benzyl-α-d-glucopyranosyl)-3-formylpropaneC38H42O6[α]D22=+36.8 (c 1.1, CH2Cl2)