Wen-Jing Xiao and co-workers from Central China Normal University have reported in JACS on an asymmetric [4+1] reaction between a copper allenylidene and sulfur ylide.
Posted by naturalproductman on February 12, 2016
Greg Fu and Jonas Peters and co-workers at Caltech have reported in Science on a copper catalyzed asymmetric C-N bond coupling reaction that required blue light.
Posted by naturalproductman on January 26, 2016
Peter Schreiner and co-workers from Justus-Liebig University have reported in ACIE on an asymmetric Dakin-West reaction. I am reminded of a similar transformation from carboxylic acid chlorides to trifluoroketones reported by Samir Zard’s group. From my own experience, the Zard reaction also works with just a carboxylic acid as the starting material (except, as pointed out – is not an asymmetric reaction).
Posted by naturalproductman on January 20, 2016
Jeannie Sun and colleague at the Hong Kong University of Science and Technology have reported in ACIE on an intramolecular Sn2 reaction to convert a symmetrical oxetane ring to a tetrahydropyran.
Posted by naturalproductman on January 19, 2016
X-ray crystallography is usually a good method to determine the relative configuration of natural products (i.e. diastereomers) containing more than one stereocenter. However, the method of determining the absolute configuration of natural products is very difficult by just using X-ray crystallography. Here’s a paper from the labs of Sylvia Urban (RMIT University) and Makoto Fujita (University of Tokyo) that reports on the use of the crystalline sponge method to determine the absolute stereochemistry of elatenyne.
Other ways to determine absolute configuration by X-ray crystallography include derivatization with a chiral reagent then crystallizing, using the effects of anomalous dispersion (Friedif values).
Posted by naturalproductman on November 10, 2015
Hiroaki Sasai and co-workers at Osaka University have reported in ACIE on a domino reaction involving the coupling between an allenoate ester and dienones.
Posted by naturalproductman on November 3, 2015
When I saw the Passerini reaction in the title, I thought of the use of an Ugi reaction in the synthesis of dysibetaine by the Kobayashi group. Bin Tan and co-workers at South University of Science and Technology in China have reported in JACS on a phosphoric acid catalyzed Passerini reaction.