Reversing the Stereoselectivity of a Palladium‐Catalyzed O‐Glycosylation through an Inner‐Sphere or Outer‐Sphere Pathway

Abstract

An efficient and concise method for the construction of various O-glycosidic bonds by a palladium-catalyzed reaction with a 3-O-picoloyl glucal has been developed. The stereochemistry of the anomeric center derives from either an inner-sphere or outer-sphere pathway. Harder nucleophiles, such as aliphatic alcohols and sodium phenoxides give β-products, and α products result from using softer nucleophiles, such as phenol.