<i>N</i>-Heterocyclic Carbene Catalyzed Annulation of Enals to Aurone Analogs: Synthesis of Cyclopentene-Fused Spirobenzofuran-3-ones
作者:K. C. Seetha Lakshmi、Jagadeesh Krishnan、C. R. Sinu、Sunil Varughese、Vijay Nair
DOI:10.1021/ol5031684
日期:2014.12.19
A nucleophilic heterocyclic carbene mediated homoenolate annulation of enals to aurone analogs leading to the efficient synthesis of cyclopentene-fused spirobenzofuran-3-ones is reported.
Spiro-Pyrrolidine-Catalyzed Asymmetric Conjugate Addition of Hydroxylamine to Enals and 2,4-Dienals
作者:Qing-Yun Dou、Yong-Qiang Tu、Ye Zhang、Jin-Miao Tian、Fu-Min Zhang、Shao-Hua Wang
DOI:10.1002/adsc.201501025
日期:2016.3.17
A spiro‐pyrrolidine‐catalyzed tandem aza‐1,4‐addition/hemi‐acetalization reaction was developed with excellent enantioselectivity (12 examples of ≥99% ee), and several substrates proceeded with higher ee (up to 10% increase) compared with the literature data. Particularly, an interesting and unusual aza‐1,6‐/oxa‐1,4‐addition for some substrates was also observed.
Enantioselective Synthesis of Polysubstituted Cyclopentanones by Organocatalytic Double Michael Addition Reactions
作者:Anqi Ma、Dawei Ma
DOI:10.1021/ol101414b
日期:2010.8.20
diphenylprolinol-catalyzed cascade double Michael addition reactions of α,β-unsaturated aldehydes with a β-keto ester bearing a highly electron-deficient olefin unit occur smoothly to afford polysubstituted cyclopentanones. This process allows formation of four contiguous stereocenters in the cyclopentanone ring in one-step with excellent enantioselectivity.
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.
N-Heterocycliccarbenes (NHCs) catalyzing aza-Claisen rearrangement of α,β-unsaturated enals with cyclic vinylogous amides under oxidative conditions generating potentially biologically active dihydropyridinone-fused uracils have been developed. This strategy represents a unique NHC-activation-based path with the use of 6-aminouracils as stable α,β-diEWG cyclic vinylogous amides for the efficient synthesis