Stereoselective Metal-Free Synthesis of β-Amino Thioesters with Tertiary and Quaternary Stereogenic Centers
作者:Annette Bahlinger、Sven P. Fritz、Helma Wennemers
DOI:10.1002/anie.201310532
日期:2014.8.11
β‐Amino thioesters are important natural building blocks for the synthesis of numerous bioactive molecules. An organocatalyzed Mannich reaction was developed which provides direct and highly stereoselective access to acyclic β2‐ and β2,3,3‐amino thioesters with adjacent tertiary and quaternary stereocenters. Mechanistic studies showed that the stereochemical course of the reaction can be controlled
Catalytic Asymmetric Construction of Vicinal Tetrasubstituted Stereocenters by the Mannich Reaction of Linear α-Substituted Monothiomalonates with Isatin <i>N</i>-Boc Ketimines
A highly diastereo- and enantioselective method for the construction of vicinaltetrasubstitutedstereocenters through the first catalytic asymmetric Mannich reaction of linear α-substituted MTMs with isatin N-Boc ketimines has been developed. This protocol provides atom-economic synthesis of less accessible 3-aminooxindoles bearing vicinaltetrasubstitutedstereocenters. Notably, it also constitutes
Organocatalytic Stereoselective Synthesis of Acyclic γ-Nitrothioesters with All-Carbon Quaternary Stereogenic Centers
作者:Yukihiro Arakawa、Sven P. Fritz、Helma Wennemers
DOI:10.1021/jo500403q
日期:2014.5.2
stereoselective synthesis of acyclic thioesters bearing adjacent quaternary and tertiary stereogeniccenters under mild organocatalytic conditions was developed. α-Substituted monothiomalonates (MTMs) were used as thioester enolate equivalents. They reacted cleanly with nitroolefins in the presence of 1–6 mol % of cinchona alkaloid urea derivatives, and provided access to γ-nitrothioesters with quaternary stereocenters