Neluka Weerasooriya

Recent advances into the enantioselective protonation of prostereogenic enol derivatives

Abstract We discuss the recent developments into the enantioselective protonation of substituted enol derivatives and comment on the effect that reaction parameters (such as solvent, temperature and salt additive) have on the facial preference.

Investigations on the Efficiency of Regioselective C-Deuteration of Endocyclic Enolates

Regioselective C-deuteration of a series of Endocyclic enolates (derived from cyclic aryl ketones) was efficiently achieved by quenching the corresponding “base-free” enolate in the presence of a suitable deuterium source. We discuss the structural nature of the deuterium donor and comment on the use of additives within this deuteration step.

Investigations into the enantioselective protonation of enolates derived from 2-methyl-1-tetralone using a chiral diamine ligand

Abstract The synthesis of enantiomerically enriched (+)-( R )-2-methyl-1-tetralone 1 (up to 47% e.e.) was achieved by enantioselective protonation of an achiral lithium enolate 3 using a chiral diamine additive in the presence of acetic acid. We discuss the factors (like salt effects and chelation) that are responsible for this observed enantioselectivity and comment on the role of the achiral acid.

Investigations into the mechanism of regioselective C-deuteriation of enolates under ‘base-free’ conditions

Abstract Regioselective C -deuteriation of enolates was efficiently achieved by quenching the corresponding base-free enolate in the presence of a carbonyl chelating deuterium source. We comment on factors (such as the presence of base and the structural nature of the deuterium reagent) that are responsible for this observed regioselectivity and comment on the role of the deuterium source.

Mechanism of enantioselective protonation of an enolate in the presence of a chiral phenolic additive

The synthesis of enantiomerically enriched (+)-(R)-2-methyl-1-tetralone 1 (up to 29% e.e.) was achieved by enantioselective protonation of the achiral enolate such as 2, using the oxazoline (S)-3 as the source of chirality. Copyright 1999 Wiley-Liss, Inc.

Short Communication: An Unusually Crystalline Enolacetate

We report the first crystal structure of a simple achiral enolacetate derivative. We discuss its structural characteristics and also comment on its conformational preference. This crystalline enolacetate (derived from tetralone and isopropenyl acetate) crystallized in an orthorhombic space group, Pbca, with cell dimensions a 9.358(2),b10.078(2), c 20.938(4) A and Z 8. This unit cell was centrosymmetric and contained an equal number of both enantiomeric conformers. Manuscript received: 26 April 2001. Final version: 6 July 2001.