Low catalyst loadings in olefin metathesis: synthesis of nitrogen heterocycles by ring-closing metathesis.
A series of ruthenium catalysts have been screened under ring-closing metathesis (RCM) conditions to produce five-, six-, and seven-membered carbamate-protected cyclic amines. Many of these catalysts demonstrated excellent RCM activity and yields with as low as 500 ppm catalyst loadings. RCM of the five-membered carbamate series could be run neat, the six-membered carbamate series could be run at 1.0 M, and the seven-membered carbamate series worked best at 0.2-0.05 M.
The Arnold and Mabel Beckman Laboratory of Chemical Synthesis, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Kevin M
KM
Kuhn
Timothy M
TM
Champagne
Soon Hyeok
SH
Hong
Wen-Hao
WH
Wei
Andrew
A
Nickel
Choon Woo
CW
Lee
Scott C
SC
Virgil
Robert H
RH
Grubbs
Richard L
RL
Pederson
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D006571:Heterocyclic Compounds / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry
D000475:Alkenes; D006571:Heterocyclic Compounds; D012428:Ruthenium; D009584:Nitrogen