Rhodium-Catalyzed Selective <i>anti</i>-Markovnikov Addition of Carboxylic Acids to Alkynes
作者:Alexandre Lumbroso、Nicolas R. Vautravers、Bernhard Breit
DOI:10.1021/ol102365e
日期:2010.12.3
The selective intermolecular anti-Markovnikov addition of carboxylic acids to terminal alkynes yielding valuable Z-enol esters has been achieved for the first time under rhodium-catalyzed conditions. The catalyst system is applicable to a broad substrate scope and displays a wide functional group tolerance.
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.
Redox-Neutral Atom-Economic Rhodium-Catalyzed Coupling of Terminal Alkynes with Carboxylic Acids Toward Branched Allylic Esters
作者:Alexandre Lumbroso、Philipp Koschker、Nicolas R. Vautravers、Bernhard Breit
DOI:10.1021/ja1108613
日期:2011.3.2
A new method for the preparation of a wide range of branched allylic esters from terminal alkynes that proceeds via a redox-neutral propargylic CH activation employing a rhodium(I)/DPEphos catalyst is reported.