Exo-selective reductive macrocyclization of ynals.
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.
Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States.
Hengbin
H
Wang
Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States.
Solymar
S
Negretti
Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States.
Allison R
AR
Knauff
Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States.
John
J
Montgomery
D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D047028:Macrocyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry; D013237:Stereoisomerism
D000480:Alkynes; D047028:Macrocyclic Compounds; C030011:carbene; D009532:Nickel; D008697:Methane