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.
Tan
Kian L
KL
Department of Chemistry, University of California and Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Park
Steve
S
Ellman
Jonathan A
JA
Bergman
Robert G
RG
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