Swapped selectivities: The use of tailor‐made catalysts results in anomalous endo/exo selectivities and high enantioselectivities in the Diels–Alder reactions of cyclopentadiene with different acroleins (see scheme). These supramolecular catalysts are prepared in situ from chiral diols, arylboronic acid, and tris(pentafluorophenyl)borane, and can discriminate the re/si face of the dienophile as well
Catalytic Enantioselective Synthesis of Difluoromethylated Tetrasubstituted Stereocenters in Isoindolones Enabled by a Multiple-Fluorine System
作者:Meng-Yu Rong、Jin-Shan Li、Yin Zhou、Fa-Guang Zhang、Jun-An Ma
DOI:10.1021/acs.orglett.0c03406
日期:2020.11.20
This unique multiple-fluorine system provides rapid access to difluoromethylated tetrasubstituted stereocenters in isoindolones with wide substrate scope under mild conditions. Further synthetic transformations to enantioenriched CF2H-isoindolones and CF2-decorated fused isoindolones were also implemented with good efficiency.
Disulfonimide-Catalyzed Asymmetric Synthesis of β<sup>3</sup>-Amino Esters Directly from <i>N</i>-Boc-Amino Sulfones
作者:Qinggang Wang、Markus Leutzsch、Manuel van Gemmeren、Benjamin List
DOI:10.1021/ja408747m
日期:2013.10.16
An asymmetric Mannich reaction of silyl ketene acetals with N-Boc-amino sulfones has been developed. A chiral disulfonirnide efficiently catalyzes both the in situ generation of the corresponding N-Boc imines and the asymmetric Mannich reaction with excellent yields and enantioselectivities. Kinetic studies confirm a proposed stepwise mechanism.