3 research outputs found
Asymmetric Construction of a Multi-Pharmacophore-Containing Dispirotriheterocyclic Scaffold and Identification of a Human Carboxylesterase 1 Inhibitor
A catalytic asymmetric [3 + 2] cyclization
of novel 4-isothiocyanato
pyrazolones and isatin-derived ketimines was developed, delivering
a wide range of intriguing dispirotriheterocyclic products in high
yield with excellent diastereoselectivity and enantioselectivity.
A chiral sulfoxide derivative of this dispirocyclic product was identified
to be a promising hit of the human carboxylesterase 1 inhibitor, and
the significant difference of the activity between two enantiomers
emphasized the importance of this asymmetric process
An Organocatalytic Asymmetric Friedel–Crafts Addition/Fluorination Sequence: Construction of Oxindole–Pyrazolone Conjugates Bearing Vicinal Tetrasubstituted Stereocenters
A highly efficient
and practical one-pot sequential process, consisting
of an organocatalytic enantioselective Friedel–Crafts-type
addition of 4-nonsubstituted pyrazolones to isatin-derived <i>N</i>-Boc ketimines and a subsequent diastereoselective fluorination
of the pyrazolone moiety, is developed. This reaction sequence delivers
novel oxindole–pyrazolone adducts featuring vicinal tetrasubstituted
stereocenters with a 0.5 mol % catalyst loading in high yield with
excellent enantio- and diastereocontrol. Notably, chloro, bromo, and
thioether functionalities can be readily incorporated, rendering a
broad diversity of the product
Enantioselective Synthesis of 2,3,3a,8a-Tetrahydrofuro[2,3‑<i>b</i>]benzofuran Scaffolds Enabled by Cu(II)/SPDO-Catalyzed [3+2] Cycloaddition of 2,3-Dihydrofuran and Quinone Esters
An
asymmetric [3+2] cycloaddition of quinone esters with 2,3-dihydrofuran
has been realized via a newly developed Cu(II)/SPDO complex. It provides
straightforward access to 2,3,3a,8a-tetrahydrofuro[2,3-b]benzofurans (TFB) with high enantioselectivity (up to 97.5:2.5 er)
and diastereoselectivity (all >20:1 dr). The resulting adducts
contain
two adjacent stereocenters and a continuously functionalized benzene
ring. Additionally, this transformation could be easily performed
on a gram scale, allowing for expedient synthesis of natural dihydroaflatoxin
D2 and aflatoxin B2