CC BY-NC-ND 4.0 · Synlett
DOI: 10.1055/a-1293-9867
letter

Determining the Relative Configuration of Propargyl Cyclopropanes by Co-Crystallization

Felix Krupp
a  Institut für Organische Chemie, Universität Stuttgart, 70569 Stuttgart, Germany
,
Marie-Idrissa Picher
a  Institut für Organische Chemie, Universität Stuttgart, 70569 Stuttgart, Germany
,
Wolfgang Frey
a  Institut für Organische Chemie, Universität Stuttgart, 70569 Stuttgart, Germany
,
Bernd Plietker
b  Organische Chemie I, Fakultät für Chemie und Lebensmittelchemie, Technische Universität Dresden, 01069 Dresden, Germany
,
Clemens Richert
a  Institut für Organische Chemie, Universität Stuttgart, 70569 Stuttgart, Germany
› Author Affiliations
This work was supported by DFG grant RI 1063/17-1.


Abstract

Determining the diastereoselectivity of new synthetic mo­lecules can be a challenge when NMR methods fail and the compounds are difficult to crystallize. Encapsulating organic crystals can be used to overcome this challenge. Here we show that the diastereomeric confi­guration of racemic mixtures of propargyl cyclopropanes can be determined by co-crystallization with 1,3,5,7-tetrakis(2-bromo-4-methoxyphenyl)adamantane and X-ray crystallography. Three crystal structures are reported that unambiguously identify the products of Fe-catalyzed cyclopropanations as cis- or trans-isomers. These findings expand the scope of co-crystallization with tetraaryladamantanes as a method to determine the stereochemical configuration of organic molecules that are difficult to crystallize by themselves.

Supporting Information



Publication History

Received: 18 September 2020

Accepted after revision: 20 October 2020

Publication Date:
20 October 2020 (online)

© 2020. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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