Recently, Li Junlong Research Group of the College of Pharmacy of Chengdu University published a study entitled Lewis Acid/Brønsted Base-assisted Palladium Catalysis: Stereoselective Construction of Skeletally Diverse spiro-ketolactams from Vinylefriction Carbonates in ACS Catalysis (Q1 journal of Chinese Academy of Sciences, impact factor: 13.084), a famous international academic journal in the catalytic field. Chengdu University is the first unit of this achievement. Huang Qianwei, a postgraduate student enrolled in 2018, is the first author of the paper, and Ph.D. Qi Ting is the co-first author, who have completed the synthesis experiment and theoretical calculation research work respectively. Distinguished researcher Li Junlong is the advisor and corresponding author of this paper.
Through rational design and extensive experimental screening, we found that Lewis Acid/Brønsted base-assisted Palladium catalytic system can achieve a variety of cyclization reactions based on vinyl carbonate and pyrrolidone derived enone substrates, and quickly construct two types of spirolactam rings, [5,5] and [5,6]. This catalytic synthesis method obtained a series of excellent enantioselective tetrahydrofuran spirolactam through the asymmetric (3 + 2) cyclization reaction co-catalyzed by Pd/Al(OiPr)3. A series of cyclohexene spironolactam was synthesized by diastereoselective (4 + 2) cyclization in the Pd/NaHCO3 catalytic system. By further derivation and transformation of the [5,5] and [5,6] spiro skeleton, the versatility and practicability of the method are demonstrated. In addition, density functional theory calculations provide a reasonable explanation for the mechanism of the catalytic system to realize different reaction paths.
It is reported that ACS Catalysis is a flagship journal sponsored by the American Chemical Society (ACS), which mainly publishes high level academic results in catalysis research. It belongs to the top journal of chemistry and the Q1 journal of the Chinese Academy of Sciences (CAS). The research achievement was strongly supported by the National Natural Science Foundation of China (NSFC) and the Talent Introduction Project of Chengdu University.