Solvent-dependent diastereoselectivities in reductions of beta-hydroxyketones by SmI2.

The reductions of a series of beta-hydroxyketones by SmI(2) were examined in THF, DME, and CH(3)CN using methanol as a proton source. Reductions in THF and DME typically lead to the syn diastereomer with DME providing higher diastereoselectivities. Reductions in CH(3)CN provided the anti diastereomer predominantly. This study reveals that solvation plays an important role in substrate reduction by SmI(2). [reaction: see text]