Related Experiment Video
Updated: Jun 22, 2026
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Synthesis of a core carbon framework of cyanosporasides A and B
Daisuke Aburano1, Fuyuhiko Inagaki, Shoichirou Tomonaga
1Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
Abstract:
Treatment of 3-(2-ethynylphenyl)prop-2-ynyl benzenesulfinate with 2.5 mol % of [RhCl(CO)(2)](2) at 40 degrees C under an atmosphere of CO effected the successive 2,3-sigmatropic rearrangement and carbonylative [2 + 2 + 1] ring-closing reaction to afford the 8-(phenylsulfonyl)-1H-cyclopent[a]-inden-2-one in a high yield. Chemical modification of the ring-closed product via lipase-mediated optical resolution produced the optically active 3-acetoxy-3a-cyclohexyloxy-3,3a-dihydrocyclopent-[a]indene skeleton, the core carbon framework of cyanosporasides A and B.
Related Concept Videos
Bacterial Phylum Cyanobacteria
Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview
Biosynthesis in Bacteria
Biosynthesis of Polysaccharides
Biosynthesis of Nucleic Acids
Aldehydes and Ketones with HCN: Cyanohydrin Formation Mechanism

