536731-06-3Relevant academic research and scientific papers
Role of cations and confinement in asymmetric photochemistry: Enantio- and diastereo-selective photocyclization of tropolone derivatives within zeolites
Joy, Abraham,Kaanumalle, Lakshmi S.,Ramamurthy
, p. 3045 - 3053 (2007/10/03)
Asymmetric induction in photochemical reactions has been explored using the photochemistry of tropolones as a model. Three approaches have been examined: chiral inductor, chiral auxiliary and [chiral inductor + chiral auxiliary]. All three methods gave excellent asymmetric induction in zeolite and very little or zero induction in solution. Results presented on tropolones clearly illustrate the remarkable influence that a confined space studded with cations can have on asymmetric induction. Tropolone derivatives, upon irradiation undergo 4π-electron electrocyclization to yield a bicyclic product and a rearranged product. Enantiomeric excess up to 68% has been achieved in the cyclized product. In systems where a chiral inductor has been covalently linked, diastereomeric excess as high as 88% has been achieved within a zeolite while the same system in solution gave 10%. The Royal Society of Chemistry 2005.
