t different carbons included X-ray crystallography and NMR.Nicolaou set about synthesizing this compound by thinking through possible reactions that he might use to begin to build the carbon skeleton needed for this molecule. His team decided on a type-II intramolecular Diels-Alder reaction as the key step to generation of the core skeleton. The Diels-Alder reaction utilizes a dienophile in order to form new carbon-carbon bonds in a single step, in this case to form multiple ring structures. However, Nicolaou ran into trouble when several reagent-based enantioselective approaches with the precursor failed to yield appreciable levels of the desired product. After much study of this problem, Nicolaou's team came to the conclusion that a Lewis acid catalyst would be their best shot at inducing the asymmetry needed for this particular absolute configuration.After several more reaction steps, the team had two diastereomeric diols in a racemic mixture that were then converted to enantiomeric aldehydes with TBAF and NaIO4 - induced oxidative cleavage. After conversion to the indoline, the synthetic compound was compared to the naturally derived compound using NMR, TLC, and IR spectroscopy. However, the optical rotation of the synthetic compound was opposite in magnitude to the naturally derived CP molecule; the synthetic compound was verified as the enantiomer of the naturally occurring compound circular dichroism spectroscopy, and thus, the absolute configuration was verified.This paper parallels Nicolaou's research goals by showing how this team determined the absolute configuration of a complex compound they synthesized from a much simpler molecule (glycidol). It also shows the importance of techniques used to determine structure and content of complex molecules, such as NMR and IR spectroscopy. ...
