Assignment of the absolute configuration of [n]-ladderanes by TD-DFT optical rotation calculations.

Published

Journal Article

In this study, we report theoretical specific rotation values for a series of cis-/trans-alkylated-[5]-ladderanes and cis-/trans-methylated-[n]-ladderanes. Using time-dependent density functional response theory optical rotation calculations, we can assign (+) and (-) optical rotation signs to trans-(S)-alkyl-[5]-ladderane and trans-(R)-alkyl-[5]-ladderane configurations, respectively. In order to qualitatively validate our absolute configuration predictions, we computed optical rotation values at three different levels of theory--B3LYP, RI-BP86, and Hartree-Fock--using the aug-cc-pVDZ basis set. We observe a novel rung-parity-controlled oscillatory optical rotatory phenomenon in our computations, which, to the best of our knowledge, has never been reported or observed before. Furthermore, this preliminary analysis of optical rotation properties in this class of compounds should facilitate the correct absolute stereochemical assignment of natural and synthetic ladderanes, such as the trans-isomer of pentacyclic C(20)-fatty acid methyl ester (pentacycloanammoxic methyl ester), without the need for derivatization, in particular for cases where NMR or X-ray crystal structures are not readily available.

Full Text

Duke Authors

Cited Authors

  • Zuber, G; Goldsmith, M-R; Beratan, DN; Wipf, P

Published Date

  • October 2005

Published In

Volume / Issue

  • 17 / 8

Start / End Page

  • 507 - 510

PubMed ID

  • 16121333

Pubmed Central ID

  • 16121333

Electronic International Standard Serial Number (EISSN)

  • 1520-636X

International Standard Serial Number (ISSN)

  • 0899-0042

Digital Object Identifier (DOI)

  • 10.1002/chir.20190

Language

  • eng