Palladium-catalyzed dicyanative [4 + 2] cycloaddition using various ene−enynes was investigated. The key species in this process is a cyanoallene intermediate that is obtained by the cyanopalladation of conjugated enynes followed by 5-exo-cyclization. To achieve an efficient [4 + 2] cycloaddition reaction, both the smooth generation of this species and critical control of regioselectivity in the 6-endo-cyclization
Rhodium‐Catalyzed [4+2+1] Cycloaddition of In Situ Generated Ene/Yne‐Ene‐Allenes and CO
作者:Zi‐You Tian、Qi Cui、Cheng‐Hang Liu、Zhi‐Xiang Yu
DOI:10.1002/anie.201805908
日期:2018.11.19
rhodium‐catalyzed [4+2+1] cycloaddition of in situ generated ene/yne‐ene‐allenes and CO to synthesize challenging seven‐membered carbocycles fused with five‐membered rings. This reaction is designed based on the 1,3‐acyloxy migration of ene/yne‐ene‐propargyl esters to ene/yne‐ene‐allenes, followed by oxidative cyclization, CO insertion, and reductive elimination to form the final [4+2+1] cycloadducts.