Enantiodivergent Steglich rearrangement of -carboxylazlactones catalyzed by a chirality switchable helicene containing a 4-aminopyridine unit.

A pseudo-enantiomeric pair of optically switchable helicenes containing a catalytic 4--methylaminopyridine (MAP) bottom unit and a -symmetric, (10,11)-dimethoxymethyl-dibenzosuberane top template was synthesized. They underwent complementary photoswitching at 290 nm (/', <1/>99) and 340 nm (/', 91/9) and unidirectional thermo-rotation at 130 °C (/', >99/<1). They were utilized to catalyze enantiodivergent Steglich rearrangement of - to -carboxylazlactones, with formation of either enantiomer with up to 91% ee () and 94% ee (), respectively.