Stereocontrolled Generation of α-Metalated S,O-Acetals by Sulfoxide-Ligand Exchange from Cyclic Dithioorthoformate Monooxides
摘要:
Treatment of trans or cis 2-isopentoxy-1,3-benzodithiolane-S-oxides with EtMgCl gave configurationally stable (>= 2.5 h, at -78 degrees C) stereodefined alpha-magnesiated S,O-acetals that incorporated D atoms in a stereospecific manner upon reaction with CD3OD. alpha-Lithiated S,O-acetals generated in the same fashion using PhLi were found to be less configurationally stable.