Direct carbon-carbon bond formation via soft enolization: a biomimetic asymmetric Mannich reaction of phenylacetate thioesters.
An asymmetric Mannich reaction of phenylacetate thioesters and sulfonylimines using cinchona alkaloid-based amino (thio)urea catalysts is reported that employs proximity-assisted soft enolization. This approach to enolization is based on the cooperative action of a carbonyl-activating hydrogen bonding (thio)urea moiety and an amine base contained within a single catalytic entity to facilitate intracomplex deprotonation. Significantly, this allows thioesters over a range of acidity to react efficiently, thereby opening the door to the development of a general mode of enolization-based organocatalysis of monocarboxylic acid derivatives.
Kohler
Mark C
MC
Department of Chemistry, Duke University, Durham, North Carolina 27708, USA.
Yost
Julianne M
JM
Garnsey
Michelle R
MR
Coltart
Don M
DM
D000588:Amines / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D002930:Cinchona Alkaloids / Q000737:chemistry*; D020650:Combinatorial Chemistry Techniques; D004952:Esters; D015394:Molecular Structure; D010648:Phenylacetates / Q000737:chemistry*; D013457:Sulfur Compounds / Q000737:chemistry*
D000588:Amines; D002930:Cinchona Alkaloids; D004952:Esters; D010648:Phenylacetates; D013457:Sulfur Compounds; D002244:Carbon