Readily available phosphoramidites incorporating TADDOL-related diols with an acyclic backbone turned out to be excellent ligands for asymmetric gold catalysis, allowing a number of mechanistically different transformations to be performed with good to outstanding enantioselectivities. This includes [2 + 2] and [4 + 2] cycloadditions of ene-allenes, cycloisomerizations of enynes, hydroarylation reactions
Rhodium‐Catalyzed Asymmetric [2+2+2] Cycloaddition Reactions of 1,6‐Enynes and Oxabenzonorbornadienes
作者:Jianxiao Ni、Jingchao Chen、Yongyun Zhou、Gaowei Wang、Sida Li、Zhenxiu He、Weiqing Sun、Baomin Fan
DOI:10.1002/adsc.201900380
日期:2019.8.5
The asymmetric [2+2+2] cycloaddition reactions of 1,6‐enynes and oxabenzonorbornadienes was accomplished by using the complex of [Rh(COD)2]BF4 and (R)‐Xyl‐P‐Phos as chiral catalyst. A range of 1,6‐enynes and oxabenzonorbornadienes were well tolerated in the cycloaddition reaction, which afforded various polycyclic products with asymmetric quaternary carbon centers generally in excellent enantioselectivities
Towards specific “cluster-like” reactivity? Ligands pre-organizing gold centers in a constrained environment, assisted by aurophilic interactions, push further the selectivity not achieved by mono- and digold complexes from previously unseen cooperative tetragold catalysis.