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Competition experiments are a useful tool for preliminary study of the linear free energy relationship of organic reactions. This article describes a physical organic experiment for upper-level undergraduates to identify the rate-determining step of the Claisen–Schmidt condensation of benzaldehyde and acetophenone by studying the linear free energy relationship. Substituent electronic effects were studied by competition experiments and the product ratios were determined by gas chromatography. Hammett plots were constructed from the relative rates, and the reaction constants (ρ) obtained in varying the substituents at the para position of benzaldehyde and acetophenone were 3.09 and 1.59, respectively. The reaction rates were found to be more sensitive to the substituents on benzaldehyde. The positive reaction constants suggested that nucleophilic addition (the first step) is the rate-determining step as the reaction rates were enhanced by increasing the electrophilicity of benzaldehyde as well as the acidity of the α-H of acetophenone.

The synthesis and resolution of the atropisomeric 1,1'-bi-2-naphthol illustrates several important concepts in organic chemistry and serves as a good experiment for organic chemistry laboratory course of intermediate to advanced levels. Racemic 1,1'-bi-2-naphthol is synthesized by the oxidative coupling of 2-naphthol and is resolved into the enantiopure form by the selective inclusion compound formation of the R enantiomer with (−)-N-benzylcinchonidinium chloride. The enantiomeric excess of the products are determined by chiral HPLC. The naphthol unit of 1,1'-bi-2-naphthol is composed of a benzene and a phenol fused together. Both 1H and 13C NMR spectra show complicated and overlapping signals in the aromatic region and complete signal assignment is extremely difficult. Unambiguous signal assignment is made possible with the help of various 2-D NMR techniques such as COSY, HMQC, and COLOC. It serves as an advanced exercise for spectroscopic structural identification of organic compounds.