Water-Enabled Catalytic Asymmetric Michael Reactions of Unreactive Nitroalkenes: One-Pot Synthesis of Chiral GABA-Analogs with All-Carbon Quaternary Stereogenic Centers
作者:Jae Hun Sim、Choong Eui Song
DOI:10.1002/anie.201611466
日期:2017.2.6
new catalytic reactions for otherwise unreactive substrate systems. Under the “on water” reaction conditions, extremely unreactive β,β‐disubstituted nitroalkenes smoothly underwent enantioselective Michael addition reactions with dithiomalonates using a chiral squaramide catalyst, affording both enantiomers of highly enantioenriched Michael adducts with all‐carbon‐substituted quaternarycenters. The
Nickel-catalyzed cross-coupling of β-carbonyl alkenyl pivalates with arylzinc chlorides
作者:Wen-Jing Pan、Zhong-Xia Wang
DOI:10.1039/c7ob02947k
日期:——
The nickel-catalyzed cross-coupling reaction of β-carbonyl alkenyl pivalates with arylzinc reagents generates 3-aryl-substituted α,β-unsaturated carbonyl compounds via C–O bond cleavage. The reaction features mild reaction conditions, a wide scope of substrates, and good functional group tolerance.
Acylated furanyl and thienyl acrylic acids, process for their production, and pharmaceutical compositions
申请人:MERRELL DOW PHARMACEUTICALS INC.
公开号:EP0046595A1
公开(公告)日:1982-03-03
This invention relates to acylated furanyl acrylic acids, salts, esters and amides, to acylated thienyl acrylic acids, salts, esters and amides, and to the process for producing said compounds. Furthermore, the invention relates to pharmaceutical compositions having hypolipidemic activity, which contain such compounds.
A Bio-Inspired, Catalytic<i>E</i>→<i>Z</i>Isomerization of Activated Olefins
作者:Jan B. Metternich、Ryan Gilmour
DOI:10.1021/jacs.5b07136
日期:2015.9.9
Herein, Nature's flavin-mediated activation of complex (poly)enes has been translated to a small molecule paradigm culminating in a highly (Z)-selective, catalytic isomerization of activated olefins using (-)-ribo-flavin (up to 99:1 Z/E). In contrast to the prominent Z -> E isomerization of the natural system, it was possible to invert the directionality of the isomerization (E -> Z) by simultaneously truncating the retinal scaffold, and introducing a third olefin substituent to augment A1,3-strain upon isomerization. Consequently, conjugation is reduced in the product chromophore leading to a substrate/product combination with discrete photophysical signatures. The operationally simple isomerization protocol has been applied to a variety of enone-derived substrates and showcased in the preparation of the medically relevant 4-substituted coumarin scaffold. A correlation of sensitizer triplet energy (ET) and reaction efficiency, together with the study of additive effects and mechanistic probes, is consistent with a triplet energy transfer mechanism.