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A Colorimetric Method for Quantifying Cis and Trans Alkenes Using an Indicator Displacement Assay
Author(s) -
Valenzuela Stephanie A.,
Crory Hannah S. N.,
Yao ChaoYi,
Howard James R.,
Saucedo Gabriel,
Silva A. Prasanna,
Anslyn Eric V.
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202101004
Subject(s) - dihydroxylation , chemistry , vicinal , boronic acid , cis–trans isomerism , wittig reaction , displacement (psychology) , diastereomer , stereochemistry , organic chemistry , chromatography , combinatorial chemistry , enantioselective synthesis , catalysis , psychology , psychotherapist
A colorimetric indicator displacement assay (IDA) amenable to high‐throughput experimentation was developed to determine the percentage of cis and trans alkenes. Using 96‐well plates two steps are performed: a reaction plate for dihydroxylation of the alkenes followed by an IDA screening plate consisting of an indicator and a boronic acid. The dihydroxylation generates either erythro or threo vicinal diols from cis or trans alkenes, depending upon their syn ‐ or anti ‐addition mechanisms. Threo diols preferentially associate with the boronic acid due to the creation of more stable boronate esters, thus displacing the indicator to a greater extent. The generality of the protocol was demonstrated using seven sets of cis and trans alkenes. Blind mixtures of cis and trans alkenes were made, resulting in an average error of ±2 % in the percentage of cis or trans alkenes, and implementing E 2 and Wittig reactions gave errors of ±3 %. Furthermore, we developed variants of the IDA for which the color may be tuned to optimize the response for the human eye.