This talk will focus on the use of circularly polarized (cp), or “chiral”, light as a supramolecular chiroptical field for the induction of asymmetry in small molecule building blocks as a continuous photochemical process. Enantioselective chiral photolysis of small molecules has already been achieved under batch, solid-phase conditions:  using synchrotron-sourced cp light, asymmetric photolytic selectivities of up to 4.2% enantiomeric excess (e.e.) have been reported. The optimal wavelengths to use for chiroptical photochemical induction with cp light for any given molecular building block are determined from the CD and anisotropy spectra for each building block of interest. These spectra have been experimentally measured for a small library of building blocks in two different solvents (water, hexafluoroisopropanol) across a range of wavelengths (130-400 nm).<br/><br/>A series of both batch and continuous photochemical processing experiments have been performed using synchrotron-sourced cp light as the sole source of chiroptical induction under a number of different conditions. A mechanism for asymmetry generation in these small molecule building blocks in solvent and methods for enhancing the initial selectivities observed will be discussed. Computational predictive tools for describing the chiroptical behavior of small molecules will also be presented.<br/>

Tunable chiroptical induction and photolysis in flow

2019 Fall National Meeting

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