In the course of upscaling the synthesis of enantiopure aryliodine precatalysts, we detected an unreported meso form of the catalysts for the first time. A new scalable route was developed to avoid epimerization of the lactamide arms, providing syntheses of the precatalysts that are both more effective and much less time-consuming. The catalysts obtained with these synthetic procedures have been employed in some published reactions, reaching the maximum ee ever reported.
Deciphering the Keys for High Enantioselectivity in Hypervalent Iodine-Catalyzed 1,2-Difunctionalization: Improved Synthesis of Ishihara–Muñiz Precatalysts
Org. Lett. 2021, 23 (16), 6429–6434, DOI: 10.1021/acs.orglett.1c02252.