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Chiral auxiliary-mediated synthesis of planar chiral [2.2]metacyclophanes

journal contribution
posted on 01.12.2021, 17:42 by Marco Blangetti, Donal O'SheaDonal O'Shea
The synthesis of planar chiral [2.2]metacyclophanes has been readily accomplished in a single synthetic step via the directed ortho metalation of a pro-chiral substituted metacyclophane. The use of (−)-menthyl chloroformate as a chiral auxiliary allows the introduction of the useful carbonyl functional group into the aryl ring, giving access to carboxy-substituted diastereomeric mixture of planar chiral [2.2]metacyclophanes. The separation of diastereoisomers has been easily accomplished by semipreparative HPLC, allowing the structural analysis of a single diastereoisomer by X-ray crystallography and NMR spectroscopy. The structural features of the planar chiral metacyclophanes and their high inversion barriers, determined at 473 K, encourage future investigations as chiral catalysts and ligands. This synthetic route complements our previously reported enantioselective synthesis avoiding the restrictive use of (−)-sparteine as the chiral inducer.

Funding

European Research Association ERA-Chemistry

Irish Research Council (IRC)

History

Comments

The original article is available at https://www.sciencedirect.com

Published Citation

Blangetti M, O’Shea D. Chiral auxiliary-mediated synthesis of planar chiral [2.2]metacyclophanes. Tetrahedron Letters. 2020;61(45)152492

Publication Date

28 September 2020

Department/Unit

  • Chemistry

Research Area

  • Surgical Science and Practice
  • Chemistry and Pharmaceutical Sciences
  • Cancer

Publisher

Elsevier

Version

  • Accepted Version (Postprint)