Catalytic Site-, Diastereo-, and Enantioselective Cascade Iodocyclization of 2-Geranylarenols.

A chiral amidophosphate-N-iodosuccinimide cooperative catalysis has been developed for the site-, diastereo-, and enantioselective iodocyclization of 2-geranylarenols with molecular iodine to give the corresponding iodo-containing polycyclic compounds with good levels of selectivity. This is the first example of a catalytic enantioselective iodocarbocyclization. A reactive chiral iodonium species is generated from molecular iodine via the dual halogen-bonding interactions with a chiral Lewis base and Lewis acid.

Halogen-Bonding Interaction between I and -Iodosuccinimide in Lewis Base-Catalyzed Iodolactonization.

The halogen-bonding interaction between I and -iodosuccinimide (NIS) stabilized by a Lewis base (LB) has been explored. H NMR, nuclear Overhauser effect (NOE), and diffusion-ordered NMR spectroscopy (DOSY) suggest the generation of a 1:1:1 assembly, LB-I-NIS. In contrast, when -iodotrifluoromethanesulfonimide (INTf) is used instead of NIS, LB-I-LB is generated.