{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T05:45:08Z","timestamp":1784612708096,"version":"3.55.0"},"reference-count":22,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2020,12,31]],"date-time":"2020-12-31T00:00:00Z","timestamp":1609372800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Our strategy to analyze the structures of natural amino acids with respect to the interaction of three different elements of chirality within the molecules was applied to the non-natural amino acid (S)-\u03b1-phenylglycine, its analogue (S)-\u03b1-phenylpropionic acid, and the drug (S)-ibuprofen. The three chirality elements are the configuration at C\u03b1, the conformation at the C\u03b1-C\u2019 bond, and the distortion of the planar carboxylic group to a flat asymmetric tetrahedron. In all three compounds, a given (S) configuration at C\u03b1 predominantly induces (M) conformation at the C\u03b1-C\u2019 bond, which in turn preferentially distorts the carboxylic group to a tetrahedron with (R) configuration. Both steps of this chirality chain display high selectivities. Due to varying co-crystallization partners, in all the structures the molecules are in different environments with respect to packing and hydrogen bonding. Nevertheless, the structural pattern and the diaselectivities of the chirality chain persist. For phenylglycine, DFT (Density Functional Theory) calculations confirm the structural results.<\/jats:p>","DOI":"10.3390\/sym13010055","type":"journal-article","created":{"date-parts":[[2020,12,31]],"date-time":"2020-12-31T14:31:49Z","timestamp":1609425109000},"page":"55","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["A Chirality Chain in Phenylglycine, Phenylpropionic Acid, and Ibuprofen"],"prefix":"10.3390","volume":"13","author":[{"given":"Henri","family":"Brunner","sequence":"first","affiliation":[{"name":"Institut f\u00fcr Anorganische Chemie, Universit\u00e4t Regensburg, 93040 Regensburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0034-0710","authenticated-orcid":false,"given":"Takashi","family":"Tsuno","sequence":"additional","affiliation":[{"name":"Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, Narashino, Chiba 275-8575, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"G\u00e1bor","family":"Bal\u00e1zs","sequence":"additional","affiliation":[{"name":"Institut f\u00fcr Anorganische Chemie, Universit\u00e4t Regensburg, 93040 Regensburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,12,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"628","DOI":"10.1002\/chir.23106","article-title":"Selective distortion of the planar group C\u03b1C\u2019(O)O to a chiral flat tetrahedron in the amino acid alanine","volume":"31","author":"Brunner","year":"2019","journal-title":"Chirality"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"696","DOI":"10.1002\/open.201800137","article-title":"The chirality chain in valine: How the configuration at the C\u03b1 position through the OcisC\u2019C\u03b1N torsional system leads to distortion of the planar group C\u03b1C\u2019(Ocis)Otrans to a flat tetrahedron","volume":"7","author":"Brunner","year":"2018","journal-title":"ChemistryOpen"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"635","DOI":"10.1002\/chir.23112","article-title":"Chirality in amino acids beyond the C\u03b1-configuration","volume":"31","author":"Brunner","year":"2019","journal-title":"Chirality"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"16199","DOI":"10.1021\/acs.joc.9b02726","article-title":"Chiral selectivity in the achiral amino acid glycine","volume":"85","author":"Brunner","year":"2019","journal-title":"J. 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