Remarkable Lewis acid mediated enhancement of enantioselectivity during free-radical reductions by simple chiral non-racemic stannanes

New chiral tin compounds containing the 2-(4-isopropyl-2-oxazolinyl)-5-phenyl ligand

“…There have been several reports concerning potentially intramolecularly coordinated tin compounds, including hydrides in which the tin atom is coordinated to nitrogen [1][2][3][4][5][6][7][8] or phosphorus [9] from the ligand. We have recently described the synthesis and NMR study of tin hydrides 1-3 containing the chiral oxazoline moiety (Fig.…”

From Marco Polo to chiral stannanes - radical chemistry for the new millennium

“…28 Of the remaining few reports, the introduction of asymmetry in the substrate through the use of chiral Lewis acid mediation, 29 . 34 To the best of our knowledge, this result represents the highest-ever reported enantioselectivity observed during any organic free-radical transformation. More extensive enantioselectivity data can be found in our recent publication.…”

“…More extensive enantioselectivity data can be found in our recent publication. 34 Molecular modelling has also played an important role in the design of novel reagents.…”

Enantioselective Radical Reactions

“…Schiesser and co-workers have evaluated the use of achiral and chiral Lewis acids in chiral hydrogen atom donor mediated reactions [53][54][55][56][57][58][59]. The Lewis acid additives greatly enhance the enantioselectivity in free radical reductions of halo esters and ketones in the presence of menthol or cholic acid-derived chiral stannanes (Scheme 17).…”