Chapter 13. Symmetry Breaking in a Heterogenous Phase: Intriguing Intermediates and Side-products During Asymmetric Amplification

Abstract

In this chapter we describe the results and the understanding provided by the use of heterogenous conditions for symmetry breaking and autocatalytic amplification in the Soai reaction. We mainly discuss the application of MOFs as nanoreactors to probe confinement effects on the catalytically active species. Encapsulated Soai aldehyde and residence of ensuing alkanol inside the crystalline host was documented with the help of ATR-IR and NMR. Kinetics show that boundary conditions in supply of reactants causes varying autocatalytic performances by formation of different aggregates with changing reaction rates and ee. In contrast, with pristine aldehyde in the pyrimidine and pyridine series analyses of crudes from the solid mixtures reveal the presence of additional compounds beside the main alkanol product, namely a chiral ester built from the original Soai alkanol. Their rise is intimately related to the alkylation reaction as absolute asymmetric amplification of alkanol product is observed with a striking intensification of handedness, and in a parallel amplification process, the chiral ester is produced with 98% ee, which suggests is potential implications in the mechanism of amplification reactions.