0000000000214282
AUTHOR
Pedro Aleman
Synthesis of chiral β-disulfoxides and their racemization with strong bases
Abstract β-Disulfoxides can be obtained from different α-sulfunylcarbanions and sulfinates. While α-unsubstituted and monosubstituted β-disulfoxides are configurationally stable in the presence of strong bases, α,α-disubstituted β-disulfoxides epimerize through an intermolecular mechanism.
Remarkable effect of lithium bromide in the enantioselective protonation with α-sulfinyl alcohols
Abstract The favourable effect of lithium bromide enhancing the facial enantioselectivity in the protonation of methyl tetralone enolate with α-sulfinyl alcohols is described. Theoretical calculations allow to propose a model to explain the stereochemical course of the protonation reaction.
ChemInform Abstract: Remarkable Effect of Lithium Bromide in the Enantioselective Protonation with α-Sulfinyl Alcohols.
Abstract The favourable effect of lithium bromide enhancing the facial enantioselectivity in the protonation of methyl tetralone enolate with α-sulfinyl alcohols is described. Theoretical calculations allow to propose a model to explain the stereochemical course of the protonation reaction.
An improved method for the asymmetric protonation of enolates with chiral α-sulfinyl alcohols/trifluoroethanol
Abstract Enantioselective protonation of 2-methyl tetralone enolate using a stoichiometric amount of 2-sulfinyl alcohol ( S , R s )- 1 as a chiral proton donor yields the corresponding chiral ketone with a high level of enantioselectivity, provided that the chiral proton donor (CPD) is regenerated with an achiral proton source (APS). In contrast, stereoselectivity was only moderate if catalytic CPD (0.2 equiv.) and an APS are used.
From Overstoichiometric to Substoichiometric Enantioselective Protonation with 2-Sulfinyl Alcohols: A View in Perspective
A general study of the enantioselective protonation of prochiral enolates with 2-sulfinyl alcohols is reported. The modification of reaction conditions to reduce drastically the amount of chiral proton source needed to obtain a good enantiomeric excess is reported. The effects of the different factors controlling the stereoselectivity are clearly established. Different protocols for enolate generation are compared.