containing functional groups such as ester, ketone, nitrile, amine, alcohol, sulfide, etc. can be used for the present ruthenium catalysis. The most significant advantage of this protocol is that the cycloaddition of unsymmetrical 1,6-diynes with one internal alkyne moiety regioselectively gave rise to meta-substituted products with excellent regioselectivity. Completely intramolecular alkyne cyclotrimerization
silicon-initiated cascade carbonylativecarbotricyclization (CO-SiCaT) process. It has also been found that the 5-7-5 fused tricyclic products can be obtained from the same type of enediynes and CO through a novel intramolecular [2+2+2+1] cycloaddition process. The characteristics of these two tricyclization processes and the fundamental differences in their reaction mechanisms are discussed. This novel higher-order
Enediynes undergo intramolecular [2+2+2] cycloaddition in the presence of cobalt(II) iodide (CoI2), manganese and an N-heterocyclic carbene (IPr) generated in situ from the corresponding imidazolium salt and butyllithium (BuLi). Polycyclic cyclohexadienes are obtained selectively. This new method represents an interesting alternative to those employing air-sensitive cyclopentadienylcobalt [CpCoL2 (L=CO
Ruthenium-Catalyzed Intramolecular [2+2+2] Cycloaddition and Tandem Cross-Metathesis of Triynes and Enediynes
作者:Wei Yuan、Yin Wei、Min Shi
DOI:10.1002/open.201300002
日期:2013.4
[2+2+2] Cycloadditions can be applied to specifically build up derivatives of benzene and cyclohexadiene and, therefore, have attracted much attention. Herein, we present an intramolecular [2+2+2] cycloaddition of triynes catalyzed by the first‐generation Grubbs ruthenium complex (Ru gen‐1), which can efficiently afford benzene derivatives in good yields under mild conditions. Moreover, we also report