Nickel nanoparticles catalyzed chemoselective Knoevenagel condensation of Meldrum’s acid and tandem enol lactonizations via cascade cyclization sequence
作者:Jitender M. Khurana、Kanika Vij
DOI:10.1016/j.tetlet.2011.05.032
日期:2011.7
A novel protocol has been reported wherein, polyethylene glycol (PEG) stabilized nickel nanoparticles have been used as catalyst for chemoselective Knoevenagel condensation of aromatic aldehydes and Meldrum’s acid to give 5-arylidene Meldrum’s acid which underwent tandem enol lactonization by Michael addition/cyclization sequence with active methylene compounds in the presence of Ni nanoparticles to
Monophosphine compound, transition metal complex thereof and production method of optically active compound using the complex as asymmetric catalyst
申请人:Carreira M. Erick
公开号:US20050277772A1
公开(公告)日:2005-12-15
The present invention provides a compound represented by the formula (I):
wherein ring A is void or a benzene ring optionally having substituent(s), R
1
and R
2
are each independently a phenyl group optionally having substituent(s), a cyclohexyl group and the like, R
3
and R
4
are each independently a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group and the like, and X is a residue represented by —OR
5
or —NHR
6
wherein R
5
and R
6
are a lower alkyl group optionally having substituent(s), an aralkyl group optionally having substituent(s) and the like, a asymmetric transition metal complex containing the compound as a ligand and a production method of optically active compound using the complex as an asymmetric catalyst.
Direct Conversion of Activated 5-Hydroxymethylfurfural into δ-Lactone-Fused Cyclopentenones
作者:Rafael F. A. Gomes、Jaime A. S. Coelho、Carlos A. M. Afonso
DOI:10.1002/cssc.201802537
日期:2019.1.24
decomposition/esterification. Experimental and computational studies suggest a domino rearrangement–lactonization reaction involving BINOL‐catalyzed lactonization as the rate‐determining step. The novel lactone‐fused cyclopenten‐2‐ones, which bear a quaternary carbon and resemble a didemnenone natural product structure, are converted into several derivatives with potential interest for the fields of synthetic
A Practical and Convenient Protocol for the Synthesis of (<i>E</i>)-α,β-Unsaturated Acids
作者:Amar R. Mohite、Ramakrishna G. Bhat
DOI:10.1021/ol402130t
日期:2013.9.6
α,β-Unsaturated acids are very useful and versatile reagents in organic synthesis. A novel, practical, and convenient catalytic protocol comprising FeCl3·6H2O (0.5 mol %) and H2O (1 equiv) in CH3NO2 is described for the rapid synthesis of α,β-unsaturated acids with high E-stereoselectivity under both microwave and conventional heating conditions with high TON and TOF values. This powerful approach
The environment-friendly condensation of Meldrum's acid and aromatic, heteroaromatic and hindered aliphatic aldehydes is performed carrying out the reaction in water at 75°C for 2 h, avoiding the addition of any catalyst.