17° SEMINARIO QUÍMICA ORGÁNICA IQUIR 2021

 SEMINARIO QUÍMICA ORGÁNICA 13-09-21

EXPOSITOR: Lic. Elida Thobokholt

TÍTULO: "Asymmetric Total Synthesis of Clionastatins A and B".

FUENTE: Wei Ju, Xudong Wang, Hailong Tian, and Jinghan Gui J. Am. Chem. Soc. 2021, 143, 13016–13021.

DÍA, HORA y LUGAR: Lunes 13 de septiembre de 2021, 18:00 h, Plataforma MEET GOOGLE.

Link: meet.google.com/bfh-poxv-bso

RESUMEN: Herein we report the first total synthesis of polychlorinated steroids clionastatins A and B, which was accomplishedasymmetrically by means of a convergent, radical fragment coupling approach. Key features of the synthesis include an Ireland-Claisen rearrangement to introduce the C5 stereocenter (which was ultimately transferred to the C10 quaternary stereocenter of the clionastatins via a traceless stereochemical relay), a regioselective acyl radical conjugate addition to join the two fragments, an intramolecular Heck reaction to install the C10 quaternary stereocenter, and a diastereoselective olefin dichlorination to establish the
synthetically challenging pseudoequatorial dichlorides. This work also enabled us to determine that the true structures of clionastatins A and B are in fact C14 epimers of the originally proposed structures.