Interactivity of Chiral Catalysts and Chiral Auxiliaries in the Cycloaddition of Activated Dienes with Aldehydes: A Synthesis of L-Glucose

Article abstract of DOI:10.1021/ja00282a035

Eu(fod)₃ and Eu(hfc)₃ catalyze the cycloaddition of a variety of aldehydes with oxygenated highly substituted butadienes.With achiral dienes, (+)-Eu(hfc)₃ shows only modest enantiofacial selectivities.Similarly, modest selectivities were observed in the reactions of several chiral dienes with aldehydes in the presence of the achiral Eu(fod)₃.However, the combination of chiral dienes with chiral (+)-Eu(hfc)₃ catalyst exhibited striking interactivities, resulting in some instances in diastereofacial excesses of 95 percent.Of the systems examined, only those dienes whose intrinsic facial selectivities are small and opposite in direction to that of the (+)-Eu(hfc)₃ catalyst exhibit useful interactivity of the two chiral components.Thus, the diastereomeric excesses observed here do not arise from strictly numerical factoring of componental preferences (simple double diastereoselectivity) but are a consequence of a "specific interactivity", inherent in the process itself.Application of these findings to the synthesis of optically pure substituted pyrans, L-glycolipids, and L-glucose is described.