Diastereoselective Synthesis of Triterpenoid 1,2,4-Trioxolanes by Griesbaum Co-ozonolysis
作者:Oxana B. Kazakova、Elmira F. Khusnutdinova、Anastasiya V. Petrova、Emil Yu. Yamansarov、Alexander N. Lobov、Alexandra A. Fedorova、Kyrill Yu. Suponitsky
DOI:10.1021/acs.jnatprod.9b00393
日期:2019.9.27
Diastereoselective synthesis of triterpenoid 1,2,4-trioxolanes by Griesbaum co-ozonolysis was shown for the first time. Ozonolysis of 2-methoxyoximes (syn-anti-isomers mixture) of allobetulin or methyl oleanoate with CF3-ketones resulted in asymmetrical spiro-1,2,4-trioxolanes as mixtures of diastereomers in yields up to 80-85%. The configuration of the spiro-C-2 center of individual ozonides was determined