Synthesis of 2-Chromanone-fused [3.2.0] Bicycles through a Phosphine-mediated Tandem [3+2] Cyclization/Intramolecular Wittig Reaction

Author(s):  
Junfeng Fu ◽  
Ingrid Rakielle Tsapy Takia ◽  
Peng Chen ◽  
Wei Liu ◽  
Chengjun Jiang ◽  
...  

A phosphine-mediated tandem [3+2] cyclization/intramolecular Wittig reaction of 3-aroylcoumarin with alkynone is described. The high efficiency of tandem process allows the synthesis of 2-chromanone-fused bicyclo[3.2.0]heptenones in moderate to high yields...

Synlett ◽  
2020 ◽  
Vol 31 (20) ◽  
pp. 2035-2038
Author(s):  
Wei Zhou ◽  
Maizhan Li

AbstractA highly efficient nucleophilic addition–O-acylation–intramolecular Wittig reaction of β-trifluoromethyl α,β-enones is disclosed. This strategy features mild reaction conditions and provides a practical transition-metal-free method to a set of biologically significant trifluoromethylated furans in high yields with diverse functional groups.


1999 ◽  
Vol 23 (8) ◽  
pp. 512-513
Author(s):  
Issa Yavari ◽  
Farahnaz Nourmohammadian

Tetraalkyl cyclobutene-1,2,3,4-tetracarboxylates, prepared by intramolecular Wittig reaction between a vinylphosphonium salt and diethyl 2-oxobutanedioate, undergo electrocyclic ring-opening reactions, in boiling toluene, to produce highly electron-deficient 1,3-dienes.


2005 ◽  
Vol 2005 (11) ◽  
pp. 733-735 ◽  
Author(s):  
Nemai C. Ganguly ◽  
Sanjoy Dutta ◽  
Mrityunjoy Datta ◽  
Prithwiraj De

Predominant ortho-selective mononitration of low-melting and liquid phenols and hydroxycoumarins in moderate to high yields has been accomplished upon grinding with solid cerium (IV) ammonium nitrate (CAN). Microwave-assisted expeditious CAN-mediated nitration of relatively high melting phenols and hydroxycoumarins with high efficiency and selectively under solvent-free conditions has been also developed to address the problems of sluggishness and low yield for these reluctant substrates.


Author(s):  
Udayakumar Veerabagu ◽  
Gowsika Jaikumar ◽  
Fushen Lu ◽  
Franck Quero

The 3 wt% CuI/BNNS catalyst exhibited high efficiency for C–H difluoromethylation reactions and enabled greener synthesis at high yields using cyrene as a solvent. Furthermore, the catalyst could be easily recovered and recycled for at least five cycles.


1980 ◽  
Vol 11 (49) ◽  
Author(s):  
K. NICKISCH ◽  
W. KLOSE ◽  
E. NORDHOFF ◽  
F. BOHLMANN

HortScience ◽  
2018 ◽  
Vol 53 (7) ◽  
pp. 1056-1061
Author(s):  
Leqi Yang ◽  
Xiao Yang ◽  
Hong Zhao ◽  
Danfeng Huang ◽  
Dongqin Tang

Overhead irrigation is widely used to water lettuce during commercial production in China but exerts potential water wastage and pollution. Subirrigation is thought as a water-saving, high-efficiency fertigation strategy. However, few studies have compared the nutritional value and nitrate content of lettuce grown using subirrigation with plants cultivated with overhead irrigation. Therefore, this study explored the ability of ebb-and-flow subirrigation strategies to produce high yields of a leafy lettuce (cultivar Biscia Rossa) with high nutritional value and low nitrate content. Lettuce plants were cultivated in an ebb-and-flow subirrigation system with different irrigation frequencies (every 2 or 3 days) and immersion times (5, 10 or 15 minutes); overhead irrigation was used as control. Ebb-and-flow subirrigation significantly enhanced several lettuce growth parameters, significantly increased the level of vitamin C, and significantly decreased the nitrate content of lettuce leaves compared with overhead irrigation. The optimal subirrigation strategy for lettuce production was irrigation every 3 days with 15 minutes immersion; this ebb-and-flow subirrigation protocol could potentially be used to save water and resources, improve yield and nutrient contents and reduce nitrate content in commercial greenhouse lettuce production.


Synlett ◽  
2018 ◽  
Vol 29 (20) ◽  
pp. 2608-2622 ◽  
Author(s):  
Wenwei Lin ◽  
Praneeth Karanam ◽  
Ganapuram Reddy

In this account, our group’s efforts towards exploring new substrates as precursors for the Wittig reaction have been discussed. Several new strategies developed by our group for the generation of requisite ylides for the Wittig reaction are highlighted. The idea behind the development of some chemoselective and diversity-oriented strategies are discussed in detail in a progressive manner. These strategies encompass a wide range of substrates that are employed for the synthesis of an array of heterocycles and multifunctional olefins and present a huge scope for their application on an industrial level.1 Introduction2 Development of New Methods to Effect Intramolecular Wittig Reaction3 Development of a Catalytic Wittig Reaction4 New Synthesis of Bis-Heteroarenes5 Direct β-Acylation of 2-Arylidene-1,3-indandiones6 Doubly Chemoselective Protocol for the Diversity-Oriented Synthesis of Coumarin Derivatives7 Conclusion


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