Influences of catalyst configuration and catalyst loading on selectivities in reactions of diazoacetamides. Barrier to equilibrium between diastereomeric conformations.

[reaction: see text] Stereoelectronic factors present a barrier to equilibrium between diastereomeric conformations resulting in differences in selectivity as a function of catalyst configuration. The bis(trimethylsilyl)-methyl protective group is inert to insertion but directs carbon-hydrogen insertion with enhanced enantiocontrol.