scholarly journals Reduction and Coupling Reactions of Carbonyl Compounds Using Samarium Metal in Aqueous Media

2001 ◽  
Vol 66 (1) ◽  
pp. 330-333 ◽  
Author(s):  
Sanjay Talukdar ◽  
Jim-Min Fang
1994 ◽  
Vol 72 (5) ◽  
pp. 1181-1192 ◽  
Author(s):  
T.H. Chan ◽  
C.J. Li ◽  
M.C. Lee ◽  
Z.Y. Wei

The development of organometallic-type reactions in aqueous media is reviewed. Coupling reactions of allyl halides with carbonyl compounds mediated by zinc, or tin, or indium in aqueous media to give homoallylic alcohols are discussed. The stereochemical outcome is compared with similar reactions in organic solvents. A concise synthesis of (+)-muscarine is used to illustrate the usefulness of aqueous organometallic-type reactions in organic synthesis. The procedure to protect–deprotect hydroxy functional groups may not be necessary in these reactions. An application in the carbohydrate area is demonstrated with the synthesis of (+)-3-deoxy-D-glycero-D-galacto-nonulosonic acid (KDN). The mechanistic possibilities of organometallic-type reactions in aqueous media are outlined.


2019 ◽  
Vol 23 (16) ◽  
pp. 1738-1755
Author(s):  
Humaira Y. Gondal ◽  
Zain M. Cheema ◽  
Abdul R. Raza ◽  
Ahmed Abbaskhan ◽  
M. I. Chaudhary

Following numerous applications of Wittig reaction now functionalized phosphonium salts are gaining attention due to their characteristic properties and diverse reactivity. This review is focused on α-alkoxyalkyl triphenylphosphonium salts: an important class of functionalized phosphonium salts. Alkoxymethyltriphenylphosphonium salts are majorly employed in the carbon homologation of carbonyl compounds and preparation of enol ethers. Their methylene insertion strategy is extensively demonstrated in the total synthesis of a wide range of natural products and other important organic molecules. Similarly enol ethers prepared thereof are important precursors for different organic transformations like Diels-Alder reaction, Claisen rearrangement, Coupling reactions, Olefin metathesis and Nazarov cyclization. Reactivity of these α-alkoxyalkylphosphonium salts have also been studied in the nucleophilic substitution reactions. A distinctive application of this class of phosphonium salts was recently reported in the phenylation of carbonyl compounds under very mild conditions. Synthesis of structurally diverse alkoxymethyltriphenylphosphonium salts with variation in alkoxy groups as well as counter anions are reported in literature. Here we present a detailed account of different synthetic methodologies for the preparation of this unique class of quaternary phosphonium salts and their applications in organic synthesis.


2020 ◽  
Vol 07 ◽  
Author(s):  
Tanmay Chatterjee ◽  
Nilanjana Mukherjee

Abstract: A natural driving force is always working behind the synthetic organic chemists towards the development of ‘green’ synthetic methodologies for the synthesis of useful classes of organic molecules having potential applications. The majority of the essential classes of organic transformations, including C-C and C-X (X = heteroatom) bond-forming crosscoupling reactions, cross dehydrogenative-coupling (CDC) mostly rely on the requirement of transition-metal catalysts and hazardous organic solvents. Hence, the scope in developing green synthetic strategies by avoiding the use of transitionmetal catalysts and hazardous organic solvents for those important and useful classes of organic transformations is very high. Hence, several attempts are made so far. Water being the most abundant, cheap, and green solvent in the world; numerous synthetic methods have been developed in an aqueous medium. In this review, the development of transitionmetal- free green synthetic strategies for various important classes of organic transformations such as C-C and C-X bondforming cross-coupling, cross dehydrogenative-coupling, and oxidative-coupling in an aqueous media is discussed.


2021 ◽  
Author(s):  
Seyyedeh Ameneh Alavi G. ◽  
Mohammad Ali Nasseri ◽  
Milad Kazemnejadi ◽  
Ali Allahresani ◽  
Mahdi HussainZadeh

The novel heterogeneous bimetallic nanoparticles of Cu–Co were synthesized and successfully applied as a recyclable magnetically catalyst in Heck, Suzuki, and C–N cross-coupling via a quick, easy, efficacious and environmentally protocol.


2001 ◽  
Vol 123 (22) ◽  
pp. 5358-5359 ◽  
Author(s):  
Mark Lautens ◽  
Amélie Roy ◽  
Koichiro Fukuoka ◽  
Keith Fagnou ◽  
Belén Martín-Matute

1995 ◽  
Vol 73 (10) ◽  
pp. 1675-1694 ◽  
Author(s):  
Dennis G. Hall ◽  
Renate Müller ◽  
Pierre Deslongchamps

The transannular Diels–Alder reaction of 15-membered macrocyclic trienes with a trans-trans-cis (TTC) olefin geometry can lead to A.B.C.[6.6.7] tricyclic products of trans-syn-trans (TST) and cis-syn-cis (CSC) stereochemistry whereas the TTT isomers can produce the trans-anti-cis (TAC) and cis-anti-trans (CAT) tricycles. In order to study the influence of the position (pro-6.6 or pro-6.7) and the nature (alkyl, alkoxymethyl, or formyl) of the dienophile substituent, a set of 10 model cyclopentadecatrienes was prepared. The synthesis of appropriately functionalized trisubstituted dienophile and diene synthons, as well as their coupling reactions affording acyclic precursors, is described in this paper (first in a series of two). A mild and efficient macrocyclization protocol yielded the required methyl- or alkoxymethyl-substituted cyclic substrates. Further transformations led to the formyl-substituted ones. In particular, the TTT macrocycles containing an enal as a dienophile could be completely isomerized to the corresponding TTC thermodynamic isomers in acidic aqueous media. Keywords: transannular, Diels–Alder, 15-membered ring, A.B.C.[6.6.7] tricycles, diterpene.


RSC Advances ◽  
2016 ◽  
Vol 6 (20) ◽  
pp. 16115-16121 ◽  
Author(s):  
Jason E. Camp ◽  
Jay J. Dunsford ◽  
Oliver S. G. Dacosta ◽  
Rebecca K. Blundell ◽  
James Adams ◽  
...  

Renewable sugar-derived palladium(0) nanoparticles (PdNPs) are effective as in situ formed catalysts for cross-coupling reactions in aqueous solutions.


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