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. The sterically demanding 3,3'-substituents of the chiral BINOL-derived amidophosphate are critical to induce the site-selective iodination at the less-hindered terminal alkenyl moiety of 2-geranylarenols.

Intermolecular Catalytic Asymmetric Iodoetherification of Unfunctionalized Alkenes

A newly prepared trinuclear Zn₃-(R,S,S)-aminoiminobinaphthoxide complex (triZn-II) catalyzed the first general intermolecular asymmetric iodoetherification of unfunctionalized alkenes. Using triZn-II, the iodoetherification reaction of unfunctionalized alkenes with o-nitrophenols proceeded smoothly to give the products with up to 92.5:7.5 er, and diene substrates were converted to the products with up to 99:1 er with the formation of a meso-isomer (dl/meso = 78/22). The chiral iodoethers gave a new platform for the synthesis of chiral morpholines.

Accessing Chiral 2,2-Disubstituted Morpholines via Organocatalytic Enantioselective Chlorocycloetherification

Chiral morpholine is an important scaffold in organic synthesis and a pharmacophore in medicinal chemistry. However, catalytic enantioselective procedure for the construction of morpholine remains sparse. We report herein a...

Asymmetric Halocyclizations of 2-Vinylbenzyl Alcohols with Chiral FLPs

By the use of a chiral frustrated Lewis pair (FLP) consisting of a chiral-diene-derived borane and ^tBu₃P as the catalyst, an asymmetric halocyclization of 2-vinylbenzyl alcohols with NBS or NIS was successfully realized. A variety of optically active 1,3-dihydroisobenofuran derivatives were obtained in high yields with up to 87% ee and could be conveniently converted to other useful chiral compounds.