Enantiomeric excess detection with (S)-3-Phenyl-2-(selenophenyl)propan-1-ol derivatizing agent via mix and shake 77Se NMR

Abstract

Neste artigo demonstramos que o composto (S)-3-fenil-2-(selenofenil)propan-1-ol pode ser empregado com sucesso como agente de derivatização quiral na determinação de excesso enantiomérico de substratos ácidos carboxílicos quirais via RMN de 77 Se. Os derivados diastereoméricos são obtidos através da mistura do agente de derivatização quiral com um substrato ácido não racêmico no próprio tubo de RMN e o excesso enantiomérico é determinado com apenas um espectro. Os melhores resultados foram os obtidos com o emprego do (S)-3-fenil-2-(selenofenil)propan-1-ol, que apresentou boas anisocronias para os sinais de selênio, variando entre Dd = 22 Hz a Dd = 211 Hz, mesmo com até 5 ligações separando o estereocentro do átomo de selênio.In this article, we demonstrate that (S)-3-phenyl-2-(selenophenyl)propan-1-ol can be successfully employed as chiral derivatizing agent for enantiomeric excess determination of chiral carboxylic acid substrates via 77 Se NMR. The required derivatives are obtained by mixing the chiral derivatizing agent with the non racemic carboxylic acid substrate directly in the NMR tube and determining the enantiomeric excess with just one spectrum. The best results were obtained with (S)-3-phenyl-2-(selenophenyl)propan-1-ol, which showed good anysochronies of the selenium signals, ranging from Dd = 22 Hz to Dd = 211 Hz, even with the stereocenter and the selenium atom five bonds apart.

Recent Advances in Multinuclear NMR Spectroscopy for Chiral Recognition of Organic Compounds

“…Ferreira and Gonçalves have carried out an inverse planning procedure to prepare a new chiral selenide alcohol as a CDA [ 88 ]. The article describes the synthesis of chiral selenide alcohol 32 in two steps ( Scheme 27 ).…”

Asymmetric Synthesis with Organoselenium Compounds – The Past Twelve Years

“…In this case, the e.e.s of the alcohols were measured by 1 H NMR spectroscopy. In a complementary variation of this approach reported by Ferreira and Gonçalves, [118] the e.e.s of chiral carboxylic acids were measured by 77 Se NMR spectroscopy after derivatization with the enantiopure hydroxyselenide 165, while Shyshkanov and Orlov [119] employed a similar method with amines 166 as resolving agents of chiral carboxylic acids via the formation of amide diastereomers. The 77 Se NMR measurement of e.e.s of amines 167, prepared by the addition of ArSeMgBr (or ArTeMgBr) to aziridines, was achieved by Silva et al [120] by converting them into diastereomeric BINOL boronates 168.…”

Application of Roof-Shape Amines as Chiral Solvating Agents for Discrimination of Optically Active Acids by NMR Spectroscopy: Study of Match–Mismatch Effect and Crystal Structure of the Diastereomeric Salts

“…The diastereomer formation for NMR analysis may be done by simply mixing the analyte and the chiral solvating agent (CSA) during the spectroscopic analysis . Even though the use of proton NMR is more commonly employed, the focus on targeting other NMR active nuclei for the purpose of determining optical purity is increasingly being studied. − The two components, the sample under investigation, and the chirally pure CSA in the solution, interact with each other through noncovalent interactions like hydrogen bonding, halogen bonding, π-stacking, van der Waals interactions, etc. The effectiveness of a good CSA to distinguish the two isomers of the analyte primarily depends on combination of these supramolecular forces, and hence, they are quite sensitive and specific in their action.…”