Application of a Recyclable Pseudoephedrine Resin in Asymmetric Alkylations on Solid Phase
作者:Panee C. Hutchison、Tom D. Heightman、David J. Procter
DOI:10.1021/jo0354950
日期:2004.2.1
A pseudoephedrine resin has been successfully employed in asymmetric alkylations on solid phase. Immobilized pseudoephedrine amides are conveniently prepared by the one-step attachment of pseudoephedrine to Merrifield resin through the hydroxyl group and subsequent acylation on nitrogen. Deprotonation and alkylation of the resin-bound amides proceeds smoothly. Ketones and alcohols are cleaved from
Evaluation of a Pseudoephedrine Linker for Asymmetric Alkylations on Solid Phase
作者:Panee C. Hutchison、Tom D. Heightman、David J. Procter
DOI:10.1021/ol0268788
日期:2002.12.1
Immobilized pseudoephedrine amides have been conveniently prepared by attachment of pseudoephedrine to Merrifield resin and acylation on nitrogen. Deprotonation and alkylation of the resin bound amides proceeds smoothly. Products were cleaved from the resin to give ketones and alcohols in high enantiomeric excess and moderate to good overall yield.
Synthesis and olfactory evaluation of optically active β-alkyl substituted γ-lactones and whiskey lactone analogues
β-alkyl substituted γ-lactones and whiskey lactone analogues were synthesized, and the odor properties were evaluated. During the preparation of the chiral intermediates, we found good reaction conditions for the highly enantioselective esterification of 3-arylmethyl-2-methyl-1-propanols to kinetically resolve them. The results of the olfactoryevaluations of the synthesized lactones revealed that the alkyl
present on the heterocyclic ring is the main target of the synthesis. The described method allows to prepare the suitable optically pure 2-substituted primary alcohol by means of a Pseudomonas fluorescens lipase-catalyzed transesterification. The obtained (2R)-alcohol was easily transformed into the (3R)-3-propylbutyrolactone, an advanced intermediate of brivaracetam. The described synthetic pathway is completed