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
Palladium-Catalyzed Suzuki−Miyaura Cross-Coupling Reactions of Enantiomerically Enriched Potassium β-Trifluoroboratoamides with Various Aryl- and Hetaryl Chlorides
作者:Gary A. Molander、Inji Shin、Ludivine Jean-Gérard
DOI:10.1021/ol101865e
日期:2010.10.1
Enantiomerically enriched potassium β-trifluoroboratoamides were synthesized as air-stable solids in greater than 95:5 dr using pseudoephedrine as the chiral auxiliary. With these chiral nucleophiles, Suzuki−Miyaura cross-coupling reactions were carried out with various aryl- and hetaryl chlorides in good to excellent yields. Moreover, the diastereoselectivities were preserved throughout the Suzuki−Miyaura
Synthesis of compounds with predetermined chirality
申请人:California Institute of Technology
公开号:US05488131A1
公开(公告)日:1996-01-30
A method for synthesizing enantiomerically enriched chemical intermediates with predetermined chirality is described. The method comprises formation of a pseudoephedrine amide, followed by stereoselective alkylation at the alpha carbon. The chiral auxiliary can then be cleaved off, affording chiral end products useful for further transformations. The enantiomeric enrichment of the chiral end products may exceed 98%, and the chiral auxiliary can be recovered. Novel amides of pseudoephedrine used in this method are also disclosed.
The Mannich reaction of variously substituted (+)-(S,S)-pseudoephedrine amides with either enolizable and nonenolizable imines smoothly afforded a series of β-substituted α-alkyl-β-amino amides with full stereochemical control. These Mannich adducts have been converted into several synthetically useful chiral building blocks like β-amino esters, β-amino acids, and β-lactams using very simple and high-yielding