作者:Vipin Kumar Singh、Tushar Kanti Chakraborty
DOI:10.1002/asia.202100144
日期:2021.4
The total synthesis of panaginsene has been accomplished in 11 linear steps starting from methyl 3,3‐dimethyl‐5‐oxocyclopent‐1‐ene‐1‐carboxylate. The key steps are a Sharpless asymmetric epoxidation and Ti(III)‐mediated reductive epoxide opening‐radical cyclization to construct the chiral quaternary carbon stereocenter followed by a very challenging HWE olefination reaction on an 1,3‐keto aldehyde
从3,3-二甲基-5-氧代环戊-1-烯-1-羧酸甲酯开始的11个线性步骤完成了洋紫藤烯的总合成。关键步骤是Sharpless不对称环氧化和Ti(III)介导的还原性环氧化物开环自由基环化反应,以构建手性季碳立体中心,然后在1,3-酮醛上进行极富挑战性的HWE烯化反应,并进行后期McMurry烯化反应用低价钛在五元环中构建高度约束的角四取代烯烃。