| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5277613 | Tetrahedron Letters | 2008 | 4 Pages |
A palladium(0)-tricyclohexylphosphine catalyzes cis-selective alkylative and arylative cyclization of alkyne-containing electron-deficient alkenes with organoboron reagents to provide five- or six-membered rings with exo tri- or tetra-substituted alkenes. The opposite stereoselectivity to that for the alkyne-aldehyde cyclization using the same reagents would result from palladacycle-forming oxidative addition of the substrates to the Pd0 catalyst followed by transmetalation with the boron reagents, protonation, and reductive elimination. The functional group compatibility, availability, stability, and non-toxicity of the reagents, and the fact that no additives are needed make the process more practical than the Ni0-catalyzed cyclization with organozinc reagents.
Graphical abstractA palladium(0)-tricyclohexylphosphine catalyzes cis-selective arylative cyclization of alkynyl enones with arylboronic acids to provide five- or six-membered rings with exo tri- or tetra-substituted alkenes.Download full-size image
