نتایج جستجو برای: phosphines

تعداد نتایج: 579  

Journal: :Inorganic chemistry 2004
Christine M Thomas Jonas C Peters

Anionic, electron-releasing phosphines that incorporate a borate counteranion within the ligand framework are promising reagents for organometallic catalysis. This report describes the synthesis of a new class of monodentate tertiary phosphines built upon the commonly employed tetraphenylborate anion. These new phosphines are highly stable and strongly electron-releasing and readily coordinate ...

Journal: :Journal of the American Chemical Society 2003
Katharine D Cooney Thomas R Cundari Norris W Hoffman Karl A Pittard M Danielle Temple Yong Zhao

This research has demonstrated the utility of a rigorously calibrated, molecular mechanics/semiempirical quantum mechanical protocol for developing stereoelectronic (Tolman) maps for phosphine ligands. A computational analysis of alkyl and aryl phosphines in common usage suggests that these ligands are quite similar stereoelectronically. A noticeable gap in the Tolman map for common phosphines ...

Journal: :Chemical communications 2014
Jie-Cheng Deng Chih-Wei Kuo Shih-Ching Chuang

Herein we have elucidated unusual and unique nucleophilic conjugate 1,3-addition reactions of surveyed oligoynoates toward phosphines through spectroscopic and single crystal X-ray diffraction analyses of three-component reaction products of oligoynoates, phosphines and aldehydes.

Journal: :Chemical communications 2010
Yinhua Huang Sumod A Pullarkat Yongxin Li Pak-Hing Leung

Chiral tertiary phosphines were synthesized by asymmetric hydrophosphination of aromatic enones catalyzed by an organopalladium complex with high yields and stereoselectivity. The procedure offers practical access to chiral tertiary phosphines.

Journal: :Journal of the American Chemical Society 2006
Vincent S Chan Ian C Stewart Robert G Bergman F Dean Toste

Ruthenium phosphido complexes have been shown to be excellent nucleophiles, reacting via two-electron processes with a variety of electrophiles. A catalytic alkylation reaction was developed using an achiral ruthenium complex, which was then elaborated into a catalytic enantioselective synthesis of P-stereogenic phosphines. These useful and synthetically challenging phosphines can now be access...

2014
Iris Wauters Wouter Debrouwer Christian V Stevens

Phosphines are an important class of ligands in the field of metal-catalysis. This has spurred the development of new routes toward functionalized phosphines. Some of the most important C-P bond formation strategies were reviewed and organized according to the hybridization of carbon in the newly formed C-P bond.

2013
Joachim Bruckmann Carl Krüger Frank Lutz

This work contributes to the systematic investigation of phosphines. In an attempt to deter­ mine the nature, shape, volume and direction of the lone pairs at the phosphorus atoms in phosphines, high resolution X-ray structure analyses of triphenylphosphine, tris(p-methoxyphenyl)phosphine, bis(2,4,6-triisopropylphenyl)phosphine, 1,1 -bis(diphenylphosphino)ethene and 4,5,6-triphenyl-4-phosphaspi...

Journal: :Dalton transactions 2016
Estela Haldón Ágnes Kozma Hendrik Tinnermann Lianghu Gu Richard Goddard Manuel Alcarazo

Mono- and dicationic phosphines have been synthesized through the reaction of chloroimidazolinium or chloroamidinium salts with secondary or primary phosphines respectively. The resulting ligands, which depict a significantly reduced donor ability compared with their neutral analogues, have been used to design Pt(II) and Au(I) complexes that effectively catalyse the hydroarylation of alkynes.

Journal: :Bioorganic & medicinal chemistry letters 2001
H Zang L Breydo K Mitra J Dannaldson K S Gates

Previous work has shown that alkylation of DNA by the antitumor agent leinamycin (1) is potentiated by reaction of the antibiotic with thiols. Here, it is shown that other soft nucleophiles such as cyanide and phosphines can also trigger DNA alkylation by leinamycin. Overall, the results suggest that reactions of cyanide and phosphines with leinamycin produce the oxathiolanone intermediate (2),...

2014
Christopher E. Henry Qihai Xu Yi Chiao Fan Tioga J. Martin Lee Belding Travis Dudding Ohyun Kwon

We have prepared two new diastereoisomeric 2-aza-5-phosphabicyclo[2.2.1]heptanes from naturally occurring trans-4-hydroxy-L-proline in six chemical operations. These syntheses are concise and highly efficient, with straightforward purification. When we used these chiral phosphines as catalysts for reactions of γ-substituted allenoates with imines, we obtained enantiomerically enriched pyrroline...

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