New Paradigm of Biomolecular Soft-interfaces as Chiral Reaction Fields for Supramolecular Asymmetric Photochirogenesis

Abstract

Asymmetric photochemistry provides us with new versatile routes to novel/strained chiral compounds. Recently, much effort has been devoted to the supramolecular photochirogenesis, exploiting the chiral environment of natural and synthetic hosts, such as cyclodextrin, modified zeolite, ds-DNA and protein. Photochirogenesis with biomolecule is particularly attractive and advantageous in view of the inherently chiral, finely-defined 3D structures. Serum albumins are the most abundant and well characterized water-soluble plasma proteins, which transport hydrophobic compounds. However, little is known about the supramolecular photochirogenesis with the protein used as chiral environment for reaction. We employed Bovine and Human Serum Albumin (BSA and HSA) as a chiral supramolecular host and 2-anthracenecarboxylate (AC) as a substrate. The photocyclodimerization of AC was performed in aqueous buffer solutions in the presence of BSA and HSA to give the [4+4] cyclodimers with high enantioselectivities of up to 90% ee.