Unsaturated Aldehydes as Alkene Equivalents in the Diels–Alder Reaction
作者:Esben Taarning、Robert Madsen
DOI:10.1002/chem.200800003
日期:2008.6.20
A one-pot procedure is described for using alpha,beta-unsaturated aldehydes as olefin equivalents in the Diels-Alder reaction. The method combines the normal electron demand cycloaddition with aldehyde dienophiles and the rhodium-catalyzed decarbonylation of aldehydes to afford cyclohexenes with no electron-withdrawing substituents. In this way, the aldehyde group serves as a traceless control element
SELECTIVE HYDROGENATION OF ALDEHYDE WITH RU/BIDENTATE LIGANDS COMPLEXES
申请人:FIRMENICH SA
公开号:US20140243526A1
公开(公告)日:2014-08-28
The present invention relates to processes for the reduction by hydrogenation, using molecular H
2
, of a C
5
-C
20
substrate containing one or two aldehydes functional groups into the corresponding alcohol or diol, characterized in that said process is carried out in the presence of —at least one catalyst or pre-catalyst in the form of a ruthenium complex having a coordination sphere of the N
2
P
2
O
2
, wherein the coordinating atoms N
2
are provided by a first bidentate ligand, the coordinating atoms P
2
are provided by a second bidentate ligand and the coordinating atoms O
2
are provided by two non-linear carboxylate ligands; and —optionally of an acidic additive.
Iridium-Catalyzed Enantioselective Allylic Substitution of Aliphatic Esters with Silyl Ketene Acetals as the Ester Enolates
作者:Xingyu Jiang、John F. Hartwig
DOI:10.1002/anie.201704354
日期:2017.7.17
Enantioselective allylic substitution with enolates derived from aliphatic esters under mild conditions remains challenging. Herein we report iridium‐catalyzed enantioselective allylation reactions of silyl ketene acetals, the silicon enolates of esters, to form products containing a quaternary carbon atom at the nucleophile moiety and a tertiary carbon atom at the electrophile moiety. Under relatively
作者:Heinrich Becker、Marcos A. Soler、K. Barry Sharpless
DOI:10.1016/0040-4020(94)01021-q
日期:1995.1
The asymmetricdihydroxylation procedure (AD) is applied to a variety of polyenes. In many cases excellent regioselectivities are obtained. The observed selectivities are rationalized in terms of electronic and/or steric effects inherent to the substrate, superimposed on the substrate's favorable or unfavorable interactions with the binding pocket of the AD ligand. Surprisingly, for medium and large
A brief synthesis of the Aplasmomycin tetrahydrofuran
作者:Sean P Bew、David W Knight、Robert J Middleton
DOI:10.1016/s0040-4039(00)00614-6
日期:2000.6
A highly stereoselective iodocyclisation of the 3-alkene-1,2-diol 9, derived from asymmetric dihydroxylation of the dienyl benzoate 8, gives the β-iodotetrahydrofuran 10 and thence the Aplasmomycin precursor 13, following deiodination and Mitsunobu inversion.