Exo-Selective Reductive Macrocyclization of Ynals
journal contributionposted on 20.03.2015 by Hengbin Wang, Solymar Negretti, Allison R. Knauff, John Montgomery
Any type of content formally published in an academic journal, usually following a peer-review process.
A general protocol for the highly exo-selective macrocyclization of ynals using a nickel/N-heterocyclic carbene catalyst system has been developed. A series of 10- to 21-membered macrocycles bearing an exomethylene substituent was synthesized in good yields with excellent regioselectivity (exo/endo >95:5). Very high levels of long-range diastereocontrol can also be achieved for some classes of macrocycles. Complementary to previously reported endo-selective macrocyclizations, this method provides accesses to exoalkylidene macrocycles from simple ynals in high selectivity.