64.Diastereoselective Total Synthesis of (±)-Schindilactone A, Part 3: The Final Phase and Completion
Dr. Wei-Wu Ren, Zhi-Xing Chen, Dr. Qing Xiao, Yong Li, Tian-Wen Sun, Zi-Yang Zhang, Qin-Da Ye, Fan-Ke Meng, Lin You, Ming-Zhe Zhao, Ling-Min Xu, Prof. Dr. Ye-Feng Tang,*, Prof. Dr. Jia-Hua Chen,*, Prof. Dr. Zhen Yang,*
The final phase for the total synthesis of (±)-schindilactone A (1) is described herein. Two independent synthetic approaches were developed that featured Pd–thiourea-catalyzed cascade carbonylative annulation reactions to construct intermediate 3 and a RCM reaction to make intermediate 4. Other important steps that enabled the completion of the synthesis included: 1) A Ag-mediated ring-expansion reaction to form vinyl bromide 17 from dibromocyclopropane 30; 2) a Pd-catalyzed coupling reaction of vinyl bromide 17 with a copper enolate to synthesize ketoester 16; 3) a RCM reaction to generate oxabicyclononenol 10 from diene 11; 4) a cyclopentenone fragment in substrate 8 was constructed through a Co–thiourea-catalyzed Pauson–Khand reaction (PKR); 5) a Dieckmann-type condensation to successfully form the A ring of schindilactone A (1). The chemistry developed for the total synthesis of schindilactone A (1) will shed light on the synthesis of other family members of schindilactone A.
