Supramolecular Architecture of an Amphiphilic Amino Alcohol as a Versatile Chiral Environment for Stereocontrolled Photoreaction of Various Anthracenes.

The photocyclodimerization of 2-anthracenecarboxylic acid has been extensively studied as a model reaction of asymmetric photochemistry. So far, numerous chiral environments have been employed to control this photoreaction, while the scope of photoreactants has been limited only to 2-anthracenecarboxylic acid and its simple esters and amides. Here, we developed a systematic series of photoreactants (2 a-d) by introducing various substituents to 2-anthracenecarboxylic acid, which showed different reactivities and selectivities depending on the substituents. By using the photoreactants 2 a-d, we evaluated the performance of a chiral environment composed of an amphiphilic amino alcohol (1), where the photocyclodimerization of 2 a-d generally proceeded in excellent regio- and enantioselectivities (71-98 % regio ratio, 76-86 % ee). Furthermore, by reacting 2 a and 2 b together in the chiral environment of 1, we succeeded in the first stereocontrolled cross-photocyclodimerization between two prochiral anthracenes (58 % chemo ratio, 83 % regio ratio, 90 % ee).