Use of Pseudoephedrine as a Practical Chiral Auxiliary for Asymmetric Synthesis
作者:Andrew G. Myers、Bryant H. Yang、Hou Chen、James L. Gleason
DOI:10.1021/ja00099a076
日期:1994.10
form tertiaryamides. In the presence of lithium chloride, the enolates of the corresponding pseudoephedrine amides undergo highly diastereoselective a1kylations with a wide range of alkyl halides to afford α-substituted products in high yields. These products can then be transformed in a single operation into highly enantiomerically enriched carboxylic acids, alcohols, and aldehydes. Lithium amidotrihydroborate
Pseudoephedrine as a Practical Chiral Auxiliary for the Synthesis of Highly Enantiomerically Enriched Carboxylic Acids, Alcohols, Aldehydes, and Ketones
作者:Andrew G. Myers、Bryant H. Yang、Hou Chen、Lydia McKinstry、David J. Kopecky、James L. Gleason
DOI:10.1021/ja970402f
日期:1997.7.1
pseudoephedrine as a practical chiral auxiliary for asymmetricsynthesis is described in full. Both enantiomers of pseudoephedrine are inexpensive commodity chemicals and can be N-acylated in high yields to form tertiary amides. In the presence of lithium chloride, the enolates of the corresponding pseudoephedrine amides undergo highly diastereoselective alkylations with a wide range of alkyl halides to
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
Alkylation of Chiral α-Hydroxy Ketones Derived from (1<i>R</i>)-(+)-Camphor. An Asymmetric Variant of the Classical Acetylene Route to Carbonyl Compounds
作者:Claudio Palomo、Mikel Oiarbide、Antonia Mielgo、Alberto González、Jesús M. García、Cristina Landa、Ainara Lecumberri、Anthony Linden
DOI:10.1021/ol0163530
日期:2001.10.1
[reaction: see text]. The asymmetric version of the traditional route for transforming acetylene into alpha-branched carbonyl compounds is now feasible for the first time. The method involves the temporary attachment of camphor to acetylene and gives a remarkably high diastereo- and enantioselectivity.
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.