Diastereoselective Synthesis of Rotationally Restricted Chiral Phenylpyridines via Intramolecular Cascade Cyclization of N-Acyliminium Ions Containing α-Amino Acid Residues

Abstract

A series of chiral phenylpyridines possessing a fused chiral bridge were synthesized diastereoselectively via cascade cyclizations, where N-acyliminium ions including an enantiopure α-amino acid residue were involved. The absolute configuration of the synthesized phenylpyridines was identified unambiguously by using nuclear Overhauser effect difference and circular dichroism (CD) measurements on the basis of literature methods.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications^® for the following free supplemental resources: Full experimental and spectral details.]

GRAPHICAL ABSTRACT

Keywords:

• Absolute configuration
• bridged phenylpyridine
• cascade cyclization
• CD measurements
• diastereoselectivity
• N-acyliminium ion
• NOE difference

ACKNOWLEDGMENTS

We thank the Beijing Municipal Commission of Education (No. JC015001200902), Beijing Municipal Natural Science Foundation (No. 710201 and No. 2122008), Basic Research Foundation of Beijing University of Technology (X4015001201101), Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality (No. PHR201008025), and Doctoral Scientific Research Start-up Foundation of Beijing University of Technology (No. 52015001200701) for financial support.