Copper Carbenoid, Reactant and Catalyst for One-Pot Diazo Ester Coupling Cascade Rearrangement of Enediynes: Formation of Two Contiguous Tetrasubstituted Stereocenters
作者:Shovan Mondal、Malek Nechab、Damien Campolo、Nicolas Vanthuyne、Michèle P. Bertrand
DOI:10.1002/adsc.201200045
日期:2012.7.9
The copper‐catalyzed reaction of enediynes with diazo esters leads to cyclic amino esters bearing two contiguous tetrasubstituted stereogenic centers through a one‐pot, five‐step cascade. Copper iodide catalyzes the formation of an intermediate 3‐alkynoate and copper carbenoid promotes its reversible isomerization to the corresponding allenoate. The alkynoate‐allenoate equilibrium is completely shifted
烯二炔与重氮酯的铜催化反应通过一锅五步的级联反应生成带有两个连续的四取代立体异构中心的环状氨基酯。碘化铜催化中间体3-链烷酸酯的形成,而类铜铜则促进其可逆异构化为相应的烯酸酯。Myers-Saito环化反应迅速消耗掉了烯基酸酯,从而使烷酸-脲基酸酯的平衡完全向右移动。然后是1,5‐H原子转移并生成双自由基。手性现象的记忆解释了高对映选择性。