Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1325621 | Journal of Organometallic Chemistry | 2008 | 9 Pages |
The reaction of Fischer carbene complexes with conjugated enediynes that feature a pendant alkene group has been examined. The reaction proceeds through carbene–alkyne coupling to generate an enyne–ketene intermediate. This intermediate then undergoes Moore cyclization to generate a chromium complexed arene diradical, which then undergoes cyclization with the pendant alkene group. The radical cyclization prefers the 6-endo mode unless radical-stabilizing groups are present to favor the 5-exo mode. The intermediate diradical species were evaluated computationally in both the singlet and triplet configurations. Arene triplet diradicals feature minimal spin density at oxygen and delocalization to chromium. The 6-endo cyclization product was kinetically and thermodynamically favored.
Graphical abstractThe reaction of Fischer carbene complexes with conjugated enediynes that feature a pendant alkene group has been examined. The reaction proceeds through carbene–alkyne coupling to generate an enyne–ketene intermediate, which undergoes Moore cyclization followed by 6-endo radical cyclization to afford fused polycyclic arenes. The intermediate diradical species were evaluated computationally in both the singlet and triplet configurations.Figure optionsDownload full-size imageDownload as PowerPoint slide