Ti-direct, powerful, stereoselective aldol-type additions of esters and thioesters to carbonyl compounds: application to the synthesis and evaluation of lactone analogs of jasmone perfumes
thiophenyl esters or thioaryl esters with aldehydes and ketones was performed (total 46 examples). The present method is advantageous from atom-economical and cost-effective viewpoints; good to excellent yields, moderate to good syn-selectivity, substrate variations, reagent availability, and simple procedures. Utilizing the present reaction as the key step, an efficient short synthesis of three lactone
Quinoline derivatives or salt thereof and remedy for cardiac diseases
申请人:Kowa Co., Ltd.
公开号:US05576324A1
公开(公告)日:1996-11-19
A quinoline derivative represented by general formula (1), a medicinally acceptable salt thereof, and a remedy for cardiac diseases containing the same: ##STR1## [wherein ring A represents a furan, dihydrofuran or dioxolane ring, and R.sup.1 represents an aminoalkyl group]. The compound (1) has a positively inotropic effect on myocardia and an antiarrhythmic effect, and can dilate blood vessels without extremely increasing the heart rate. Therefore, a remedy for cardiac diseases containing the same as the active ingredient is remarkably useful for treating cardiac insufficiency, arrhythmia, and so forth.
A ligand‐directed divergent scaffold synthesis was explored by varying the ligands for the gold(I) catalysts and the nucleophiles in the cycloisomerization reactions of oxindole based 1,6‐enynes. The strategy afforded several distinct and structurally complex molecular scaffolds.
Transition-State Charge Stabilization through Multiple Non-covalent Interactions in the Guanidinium-Catalyzed Enantioselective Claisen Rearrangement
作者:Christopher Uyeda、Eric N. Jacobsen
DOI:10.1021/ja110842s
日期:2011.4.6
mechanism by which chiral arylpyrrole-substituted guanidinium ions promote the Claisenrearrangement of O-allyl α-ketoesters and induce enantioselectivity was investigated by experimental and computational methods. In addition to stabilization of the developing negative charge on the oxallyl fragment of the rearrangement transition state by hydrogen-bond donation, evidence was obtained for a secondary
[reaction--see text] A new strategy for the synthesis of 2,3-disubstituted cyclopentenones emerges from two key reactions-the ruthenium-catalyzed three-component coupling of an equivalent of HBr, an alkyne, and a vinyl ketone and the Ni-Cr Barbier type reaction. As a result, these important structures are readily accessed from an alkyne and a vinyl ketone (which derive directly from carboxylic acids)