Solvent Effect in the Synthesis of Sialosyl α(2–6) Galactosides: Is Acetonitrile the only Choice?

In spite of notable achievements for the synthesis of α‐sialosides that have been made in the past decades, sialylation reactions often require low temperatures (–40 to –78 °C) and the use of acetonitrile as a solvent. Herein we report that a C‐5 oxazolidinone sialosyl donor gives high yields andstereoselectivities in the presence of dichloromethane and/or tetrahydrofuran at 0 °C. Surprisingly, high stereoselectivities and yields are obtained even at ambient temperature in tetrahydrofuran.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)