نتایج جستجو برای: stable phosphorus ylides

تعداد نتایج: 300743  

Journal: :Organic & biomolecular chemistry 2011
Richard Herchl Martin Stiftinger Mario Waser

In comparison to the use of sulfur ylides, the use of ammonium ylides for the synthesis of epoxides is significantly less developed. As a part of our systematic investigations concerning the use of amide-stabilised ammonium ylides for the synthesis of glycidic amides we have focused on the identification of the best-suited amino leaving group for this purpose. Whereas tertiary amines like quinu...

Journal: :Physical chemistry chemical physics : PCCP 2014
Yunzhou Xue Bin Wu Hongtao Liu Jiahui Tan Wenping Hu Yunqi Liu

Large-area substitutional phosphorus-nitrogen co-doped monolayer graphene is directly synthesized on a Cu surface by chemical vapor deposition using molecules of phosphonitrilic chloride trimer as the phosphorus and nitrogen sources. The doping levels of both phosphorus and nitrogen atoms decrease as a function of the growth temperature. In contrast, the doping effect is enhanced with temperatu...

2014
Natalie K. Machamer Xiaoxi Liu Stephen P. Waters

The first examples of azomethine ylides derived from allylic amine and glyoxal precursors are reported. The condensation of primary allylic and α-aryl amines with glyoxylates or α-aryl glyoxals affords conjugated azomethine ylides that undergo facile [3 + 2] cycloaddition, providing 5-alkenyl pyrrolidine cycloadducts that cannot be accessed through the classical use of amino esters as ylide pre...

Journal: :Organic & biomolecular chemistry 2006
Raphaël Robiette Matteo Conza Varinder K Aggarwal

Diastereoselectivity in reactions of aryl-stabilised ammonium ylides are highly sensitive to the nature of the amine and the ylide substituent. DFT calculations are consistent with a mechanism in which reversibility in betaine formation [despite the high energy (and therefore instability) of ammonium ylides] is finely balanced due to the high barrier to ring closure.

Journal: :Polymer Chemistry 2022

Readily available poly(sulfur ylides) are described as a new class of zwitterionic polymers that show distinct solution and thermal behavior.

Journal: :Organic & biomolecular chemistry 2005
Frances Heaney Tomas McCarthy Mary Mahon V McKee

A novel synthesis of 1,2-disubstituted 1,2-dihydroquinazoline 3-oxides 8 and the first ever examples of 1,3-dipolar trapping of these nitrones to homonuclear dipolarophiles is described. The new dipoles 8 reacted with N-methyl maleimide, generating diastereomeric adducts 14-16. In the reaction between 8 and dimethyl acetylenedicarboxylate, primary cycloadducts 17 and/or stable rearrangement pro...

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