Enantioselective Redox-Neutral Rh-Catalyzed Coupling of Terminal Alkynes with Carboxylic Acids Toward Branched Allylic Esters
作者:Philipp Koschker、Matthias Kähny、Bernhard Breit
DOI:10.1021/jacs.5b01131
日期:2015.3.4
We report on the first enantioselective variant of the atom-economic and redox-neutral coupling of carboxylic acids with terminal alkynes under rhodium catalysis utilizing the chiral, bidentate (R,R)-Cp-DIOP ligand. This represents the first example of this convenient asymmetric access to valuable branched allylic esters. The utility of this methodology is demonstrated by both a reaction performed on large scale and a short three-step synthesis of two naturally occurring gamma-butyrolactones. A stereochemical model explaining the observed absolute configuration of the products based on DFT calculations is given.