Thermal Claisen rearrangement studies on 4,6- and 2,4-diacetylresorcinol bisallyl ethers: observation of loss or [1,5] sigmatropic shift of acetyl groups

1988 ◽  
pp. 623 ◽  
Author(s):  
Ammanamanchi S. R. Anjaneyulu ◽  
Uppuluri V. Mallavadhani
Keyword(s):  
Claisen Rearrangement ◽  
Sigmatropic Shift

Total Synthesis of (±)-Cassumunins A–C and Curcumin Analogues

Synthesis ◽  
2020 ◽  
Vol 52 (10) ◽  
pp. 1561-1575 ◽  
Author(s):  
Faiz Ahmed Khan ◽  
Mulla Althafh Hussain
Keyword(s):  
Total Synthesis ◽  
Claisen Rearrangement ◽  
Aldol Condensation ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Full Account ◽  
Curcumin Analogues ◽  
Cross Coupling Reaction ◽  
Sigmatropic Shift ◽  
Novel Approaches

A full account of the total synthesis of (±)-cassumunins A–C – superior antioxidants and anti-inflammatory agents – is given. Two novel approaches were developed for synthesizing cassumunins. The total synthesis of cassumunins A and B was accomplished in five linear steps from a known aldehyde in good overall yields of 50 and 43%, respectively, featuring a cascade [3,3]-sigmatropic shift (the Claisen rearrangement) and Heck cross-coupling reaction. Consequently, the total synthesis of cassumunin C was accomplished in three linear steps from a known alcohol with an overall yield of 53%. The key features involved in this synthesis are tandem [3,3]-sigmatropic shift, SN2′ reaction, and aldol condensation. Moreover, a total of eighteen symmetrical and unsymmetrical curcumin analogues were synthesized.

α-Alkoxyalkyl Triphenylphosphonium Salts: Synthesis and Reactions

2019 ◽  
Vol 23 (16) ◽  
pp. 1738-1755
Author(s):  
Humaira Y. Gondal ◽  
Zain M. Cheema ◽  
Abdul R. Raza ◽  
Ahmed Abbaskhan ◽  
M. I. Chaudhary
Keyword(s):  
Carbonyl Compounds ◽  
Claisen Rearrangement ◽  
Alder Reaction ◽  
Coupling Reactions ◽  
Phosphonium Salts ◽  
Organic Transformations ◽  
Enol Ethers ◽  
Wide Range ◽  
Synthetic Methodologies ◽  
Alkoxy Groups

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.

Total Synthesis of Icaritin via Microwave-assistance Claisen Rearrangement

2014 ◽  
Vol 11 (9) ◽  
pp. 677-681 ◽  
Author(s):  
Van-Son Nguyen ◽  
Ling Shi ◽  
Yue Li ◽  
Qiu-An Wang
Keyword(s):  
Total Synthesis ◽  
Claisen Rearrangement ◽  
Microwave Assistance

Copper-catalyzed alkynylation/annulation cascades of N-allyl ynamides: regioselective access to medium-sized N-heterocycles

2021 ◽  
Vol 8 (1) ◽  
pp. 18-24
Author(s):  
Xu-Heng Yang ◽  
Jian Huang ◽  
Fang Wang ◽  
Zhuoliang Liu ◽  
Yujiao Li ◽  
...  
Keyword(s):  
Claisen Rearrangement ◽  
Synthetic Strategy ◽  
Key Steps

A synthetic strategy based on sequential application of aza-Claisen rearrangement, C–H functionalization, C–N coupling and cyclization as key steps has been developed for the synthesis of 6-, 7-, 8-, and 9-membered rings N-heterocycles.

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