Additional pitfalls of using 1,1-ADEQUATE for structure elucidation

Ryan D Cohen; Josep Saurí; Chelsea A Huff; Shane W Krska; Gary E Martin

doi:10.1002/mrc.4470

Additional pitfalls of using 1,1-ADEQUATE for structure elucidation

Magn Reson Chem. 2016 Nov;54(11):897-900. doi: 10.1002/mrc.4470. Epub 2016 Jul 10.

Authors

Ryan D Cohen¹, Josep Saurí², Chelsea A Huff^{3

4}, Shane W Krska³, Gary E Martin⁵

Affiliations

¹ Department of Process Chemistry, Merck Research Laboratories, 126 East Lincoln Ave., Rahway, NJ, 07065, USA. ryan.cohen@merck.com.
² Department of Process Chemistry, Merck Research Laboratories, 126 East Lincoln Ave., Rahway, NJ, 07065, USA. josep.sauri.jimenez@merck.com.
³ Department of Medicinal Chemistry, Merck Research Laboratories, 126 East Lincoln Ave., Rahway, NJ, 07065, USA.
⁴ DuPont Crop Protection, Stine-Haskell Research Center, 1090 Elkton Rd., Newark, DE, 19714, USA.
⁵ Department of Process Chemistry, Merck Research Laboratories, 126 East Lincoln Ave., Rahway, NJ, 07065, USA.

PMID: 27396947
DOI: 10.1002/mrc.4470

Abstract

1,1-ADEQUATE is a powerful and robust NMR experiment to establish carbon-carbon connectivities using modest sample quantities when cryogenic probe technology is available. Yet potential pitfalls of applying this method are not widely appreciated, such as weak or missing ¹ J_CC correlations in strongly coupled ¹³ C-¹³ C AB spin systems and unusually large multi-bond (ⁿ J_CC ) correlations associated with particular functional groups. These large ⁿ J_CC correlations observed in 1,1-ADEQUATE spectra could be mistaken for ¹ J_CC correlations. Copyright © 2016 John Wiley & Sons, Ltd.

Keywords: 1,1-ADEQUATE; 3JCC correlations; DFT calculations; INADEQUATE; J-modulated ADEQUATE.