title: Diastereoselective photocycloaddition of axially chiral monothiosuccinimides to 1,1-diphenylethylene.
abstract: Photolysis of axially chiral monothiosuccinimides in the presence of diphenylethylene gave spirothietanes effectively, where the cycloaddition took place diastereoselectively by way of the steric effect of the ortho-substituent on the phenyl ring.