A Discovery-Based Friedel-Crafts Acylation Experiment: Student-Designed Experimental Procedure

Abstract

A discovery-based Friedel–Crafts acylation experiment that includes a student-designed procedure, spectroscopic analysis of an unknown aromatic product, and molecular modeling is described. Students design the synthetic procedure and workup for the acylation of an unknown aromatic starting material in an instructor-guided classroom discussion that integrates concepts from the first semester of organic lab into a new context. The reaction proceeds in 50–85% isolated yield following a simple extractive workup. 1H NMR spectroscopy is used to identify the para-substituted acetophenone product, which leads to the identification of the starting material. Semi-empirical calculations are performed on molecular models of the ortho- and para-substituted acetophenone isomers to assess the thermodynamic stability of each, providing an explanation for the lack of ortho isomer in the reaction.