Rhodium-Catalyzed Enantioselective Synthesis of Oxazinones via an Asymmetric Ring Opening-Lactonization Cascade of Oxabicyclic Alkenes
作者:Andy Yen、Anh Hoang Pham、Egor M. Larin、Mark Lautens
DOI:10.1021/acs.orglett.9b02819
日期:2019.9.20
The rhodium-catalyzed asymmetricring opening reaction of oxabicyclic alkenes is shown to be an efficient method for synthesizing chiral heterocycles. We demonstrate that the pairwise combination of chiral catalyst with chiral amino-acid-derived pronucleophiles results in a stereodivergent synthesis of diastereomeric hydroxyesters. A favorable conformational preference induces the subsequent lactonization
Modulating chitin synthesis in marine algae with iminosugars obtained by SmI<sub>2</sub> and FeCl<sub>3</sub>-mediated diastereoselective carbonyl ene reaction
were tested. For samarium diiodide we observed a superior stereoselectivity in comparison to iron(III) chloride and methylaluminium dichloride. To increase water solubility for testing and measurement of enzyme activity, the cyclization products were further functionalized. We established a novel biological chitin synthesistest system which allows quantitative investigation of chitin synthesis in the