Asymmetric addition of chiral boron-ate complexes to cyclic iminium ions

Maziar Mohiti, Konstantinos Rampalakos, Katie M J Feeney, Daniele Leonori, Varinder K. Aggarwal*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

34 Citations (Scopus)
324 Downloads (Pure)

Abstract

Boron-ate complexes derived from enantioenriched secondary benzylic boronic esters and aryl lithiums have been reacted with quinolinium, pyridinium and dihydroisoquinolinium salts to give enantioenriched heterocyclic structures with very high diastereocontrol over two contiguous stereogenic centres (87: 1 3-99 : 1 dr; >95 : 5 es). The salts were derived from the corresponding heterocycle and Troc-Cl or dimethylTroc-Cl. In the case of the quinolinium and pyridinium salts, the presence of a 3-carboxyamide group increased both reactivity and diastereoselectivity. The unusually high diastereoselectivity observed is thought to originate from strong cation-p interactions between the cationic heterocycle and the electron rich benzylic boronate complex with minimisation of steric interactions between the substituents on the ate complex and the non-planar substituents on the heterocycle.

Original languageEnglish
Pages (from-to)602-607
Number of pages6
JournalChemical Science
Volume5
Issue number2
Early online date27 Sep 2013
DOIs
Publication statusPublished - 2014

Structured keywords

  • BCS and TECS CDTs

Keywords

  • ENANTIOSELECTIVE ADDITION
  • ISOQUINOLINE ALKALOIDS
  • KINETIC RESOLUTION
  • GRIGNARD-REAGENTS
  • TERMINAL ALKYNES
  • SALTS
  • 1,4-DIHYDROPYRIDINES
  • ALCOHOLS
  • CATALYST
  • PYRIDINE

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