Intermolecular coupling of alkenes to heterocycles via C-H bond activation.
The intermolecular coupling of unactivated alkenes to a range of heterocycles using a Rh(I) catalyst was investigated. A variety of functional groups were incorporated into the alkene, including esters, nitriles, acetals, and phthalimide. Furthermore, the heterocycle tolerated substitution with both electron-rich and electron-deficient groups. The intermolecular coupling became possible after it was discovered that weak acids dramatically increase the rate of both the inter- and intramolecular reactions. An extensive optimization of additives was performed, and HCl.PCy(3) (Cy = cyclohexyl) and HCl.P-t-Bu(2)Et were in general found to be the best additives for the reaction.
Department of Chemistry, University of California and Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Kian L
KL
Tan
Steve
S
Park
Jonathan A
JA
Ellman
Robert G
RG
Bergman
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D006571:Heterocyclic Compounds / Q000138:chemical synthesis*; D015394:Molecular Structure; D012238:Rhodium / Q000737:chemistry; D012997:Solvents / Q000737:chemistry
D000475:Alkenes; D006571:Heterocyclic Compounds; D012997:Solvents; D012238:Rhodium