Oxazolidinone acrylamides undergo addition reactions with alkyl iodide
s and allyltributylstannane to give 12-substituted products with a thr
eo preference in excess of 10:1. This threo preference is highest for
reactions carried our in nonpolar solvents, a result consistent with d
ipolar stabilization of the transition stare leading to the threo prod
uct.