43119-82-0Relevant academic research and scientific papers
Total Synthesis of Limonin
Yamashita, Shuji,Naruko, Akito,Nakazawa, Yuki,Zhao, Le,Hayashi, Yujiro,Hirama, Masahiro
, p. 8538 - 8541 (2015)
Limonoids are highly oxygenated C13α-triterpenes and common secondary metabolites. Several hundred congeners have been isolated to date. The first total synthesis of (±)-limonin, the flagship congener of the limonoids, is now reported and features 1) a tandem radical cyclization generating the BCD ring system with the C13α configuration that is essential to the limonoids and a Robinson annulation to construct the limonoid androstane framework, 2) a singlet-oxygen cycloaddition and a Baeyer-Villiger oxidation to synthesize the highly oxidized D ring, and 3) a Surez reaction to construct the unique AA′ ring system.
Asymmetric Total Synthesis of (-)-Spirochensilide A, Part 1: Diastereoselective Synthesis of the ABCD Ring and Stereoselective Total Synthesis of 13(R)-Demethyl Spirochensilide A
Liang, Xin-Ting,Sun, Bao-Chuan,Liu, Chang,Li, Yuan-He,Zhang, Nan,Xu, Qian-Qian,Zhang, Zhong-Chao,Han, Yi-Xin,Chen, Jia-Hua,Yang, Zhen
, p. 2135 - 2157 (2021)
A concise and diastereoselective construction of the ABCD ring system of spirochensilide A is described. The key steps of this synthesis are a semipinacol rearrangement reaction to stereoselectively construct the AB ring system bearing two vicinal quaternary chiral centers and a Co-mediated Pauson-Khand reaction to form the spiro-based bicyclic CD ring system. This chemistry leads to the stereoselective synthesis of 13(R)-demethyl spirochensilide A, paving the way for the first asymmetric total synthesis of (-)-spirochensilide A.
Alternative synthetic approaches to rac-progesterone by way of the classic Johnson cationic polycyclization strategy
Slegeris, Rimantas,Dudley, Gregory B.
supporting information, p. 3666 - 3672 (2016/06/06)
Three alternative synthetic entries into Johnson's classic synthesis of rac-progesterone are presented in this manuscript. ent-Progesterone, the non-natural enantiomer of progesterone, has recently been identified as a potential alternative to progesterone for investigations into possible prevention and treatment of traumatic brain injury (TBI). Difficulties in accessing ent-progesterone in large quantities prevent it from being studied more thoroughly. Strategies for producing synthetic rac-progesterone are described and discussed herein.
Chemo-enzymatic enantio-convergent asymmetric synthesis of (R)-(+)-Marmin
Edegger, Klaus,Mayer, Sandra F.,Steinreiber, Andreas,Faber, Kurt
, p. 583 - 588 (2007/10/03)
Asymmetric biohydrolysis of trisubstituted terpenoid oxiranes (rac-1a-rac-3a) was accomplished by employing the epoxide hydrolase activity Rhodococcus and Streptomyces spp. Depending on the biocatalyst, the biohydrolysis proceeded in an enantio-convergent fashion and gave the corresponding vic-diols in up to 97% ee at conversions beyond the 50%-threshold. In order to avoid a depletion of the ee of product by further oxidative metabolism, bioconversions had to be conducted in an inert atmosphere with exclusion of molecular oxygen. The synthetic applicability of this method was demonstrated by the asymmetric total synthesis of the monoterpenoid coumarin (R)-(+)-Marmin in 95% ee.
