نتایج جستجو برای: phosphines
تعداد نتایج: 579 فیلتر نتایج به سال:
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 ...
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 ...
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.
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.
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...
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.
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...
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.
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),...
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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