Epoxides as Dual-Functionalized Alkylating Reagents in Catellani Reactions for the Assembly of Heterocycles

Synlett ◽  
2020 ◽  
Vol 31 (09) ◽  
pp. 829-837 ◽  
Author(s):  
Hong-Gang Cheng ◽  
Qianghui Zhou ◽  
Chenggui Wu
Keyword(s):  
Carboxylic Acid ◽  
Catalytic System ◽  
Potassium Salt ◽  
Salient Features ◽  
Alkylating Reagents ◽  
Straightforward Approach

Reported is a cooperative catalytic system consisting of a complex of Pd with dicyclohexyl(2′,4′,6′-triisopropylbiphenyl-2-yl)phosphine (XPhos) and the potassium salt of 5-norbornene-2-carboxylic acid that permits the use of epoxides as dual-functionalized alkylating reagents in Catellani-type reactions for the assembly of heterocycles. Salient features of this research include readily available substrates, use of the potassium salt of 5-norbornene-2-carboxylic acid as a catalytic mediator as well as a base, and excellent regioselectivity for the cleavage of epoxides. This mild, chemoselective, scalable, atom- and step-economic protocol offers a straightforward approach for the assembly of isochroman and 2,3-dihydrobenzofuran scaffolds.

Alkyl Tosylates as Alkylating Reagents in the Catellani Reaction

Synthesis ◽  
2020 ◽  
Vol 52 (06) ◽  
pp. 834-846 ◽  
Author(s):  
Qianwen Gao ◽  
Ze-Shui Liu ◽  
Yu Hua ◽  
Siwei Zhou ◽  
Hong-Gang Cheng ◽  
...  
Keyword(s):  
Catalytic System ◽  
Aryl Iodides ◽  
Alkylating Reagents

A cooperative catalytic system involving a Pd/XPhos complex and inexpensive 5-norbornene-2-carbonitrile that enables the use of alkyl tosylates as alkylating reagents in the Catellani reaction has been developed. This mild, scalable protocol is compatible with a range of readily available functionalized aryl iodides and alkyl tosylates, as well as terminating olefins (45 examples, up to 97% yield).

scholarly journals Synthesis of higher carboxylic acids from ethers, CO2 and H2

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ying Wang ◽  
Qingli Qian ◽  
Jingjing Zhang ◽  
Bernard Baffour Asare Bediako ◽  
Zhenpeng Wang ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Catalytic System ◽  
Acid Synthesis ◽  
Alternative Strategy ◽  
Mechanistic Study ◽  
Rwgs Reaction ◽  
Alkyl Iodides

AbstractSynthesis of higher carboxylic acids using CO2 and H2 is of great importance, because CO2 is an attractive renewable C1 resource and H2 is a cheap and clean reductant. Herein we report a route to produce higher carboxylic acids via reaction of ethers with CO2 and H2. We show that the reaction can be efficiently catalyzed by an IrI4 catalyst with LiI as promoter at 170 °C, 5 MPa of CO2 and 2 MPa of H2. The catalytic system applies to various ether substrates. The mechanistic study indicates that the ethers are converted to olefins, which are further transformed into alkyl iodides. The higher carboxylic acids are produced by carbonylation of alkyl iodides with CO generated in situ via RWGS reaction. This report offers an alternative strategy of higher carboxylic acid synthesis and CO2 transformation.

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