Showing papers by "Jian Zheng published in 2014"
TL;DR: In this paper, the Wittig reaction of aldehydes with difluoromethyltriphenylphosphonium bromide leading to gem-difluorsoolefins in moderate yields is described.
42 citations
TL;DR: In this article, a PDFA was used to obtain trifluoromethylate terminal alkynes in the presence of Cu(I) and potassium fluoride, and the transformation proceeded smoothly.
Abstract: Difluoromethylene phosphobetaine (Ph3P+CF2CO2−, PDFA), a known difluorocarbene reagent, was found to be able to efficiently trifluoromethylate terminal alkynes in the presence of Cu(I) and potassium fluoride. The transformation proceeded smoothly to afford the corresponding trifluoromethylated acetylenes in moderate yields.
29 citations
TL;DR: In this paper, a tetrafunctional linking agent (PETP) was prepared by the reaction of pentaerythritol (PE) and propargyl bromide, and then a four arm β-CD terminated star polymer (PE-CD) was obtained through the click chemistry reaction.
Abstract: Novel macromolecular star polymers with triazole and cyclodextrin (CD) segments as branch points and poly(oligo(ethylene glycol)methacrylate) (POEGMAs) as dense hydrophilic branches were synthesized via a combination of azide–alkyne click chemistry and atom transfer radical polymerization (ATRP). Firstly, a tetrafunctional linking agent (PETP) was prepared by the reaction of pentaerythritol (PE) and propargyl bromide, and then a four arm β-CD terminated star polymer (PE-CD) was obtained through the click chemistry reaction. Finally, thermally-responsive star polymers (PE-CD–POEGMAs) with PE as the central core, triazole and CD segments as branch points, and POEGMAs as side branches were synthesized by the ATRP of MEO2MA and OEGMA using PE-CD terminated with bromines as macroinitiators. A study on the thermoresponsivity and morphology of PE-CD–POEGMAs indicated that polymeric nano-aggregates existed as multimolecular micelles and behaved with tunable thermosensitivity, which were driven by the strong hydrophobic–hydrophilic interactions in the inner core and outer shell. The encapsulation capacities towards multi-guest molecules were investigated and the results indicated that water soluble guests could be encapsulated by PE-CD–POEGMAs, and the guest encapsulation capacities were derived from the special star molecular structure properties of PE-CD–POEGMAs and the synergistic encapsulation phenomenon of different guest molecules. This unique amphiphilic star polymer illustrated the potential applications in supramolecular science, drug delivery and other nanotechnology applications.
13 citations
TL;DR: In this paper, the conversion of the difluoromethylene ylide precursor (II) to diffluorocarbene was studied to enable the synthesis of dif fluorocyclopropenes (III, IV, V, VI, VII, VIII, IX, and IX).
Abstract: The conversion of the difluoromethylene ylide precursor (II) to difluorocarbene is studied to enable the synthesis of difluorocyclopropenes (III) or the difluoromethyl substituted compounds (V), (VII) and (IX).
9 citations
Patent•
06 Aug 2014
TL;DR: In this article, a synthesis method of a novel novel difluoromethylene phosphate salt, and an application of the novel DIFFLORME phosphate salt was presented.
Abstract: The invention provides a synthesis method of a novel novel difluoromethylene phosphate salt, and an application of the novel difluoromethylene phosphate salt. The above compound has a structure represented by formula A; and in the formula A, all substituents are defined as in the specification. The invention also provides a difluorocarbene generation method and a difluoroolefination method. The compound of the formula A is used in the introduction of difluoro substituted alkyl group or a difluoro substituted alkenyl group into a molecule in the synthesis as a difluororeagent and difluoroolefination agent. A reaction using the difluoromethylene phosphate salt as a reagent has the advantages of mild conditions, high yield and wide application values.
3 citations
Patent•
07 Aug 2014
TL;DR: In this paper, the synthesis and application of difluoro methylene phosphorus inner salt was described, where the compound has a structure shown in Formula A: (R1R2R3)P+CF2CO2 -.
Abstract: The present invention provides synthesis and application of difluoro methylene phosphorus inner salt, wherein the compound has a structure shown in Formula A: (R1R2R3)P+CF2CO2 -. The definitions of substituent groups are described in the specification. The present invention also provides a method for preparing difluorocarbene and a method for difluoro alkenylation. The compound in Formula A is used as a difluorocarbene reagent and a difluoro alkenylation reagent, and during synthesis, difluoro substituted alkyl or difluoro substituted alkenyl is introduced in molecules. The reaction condition of the difluoro methylene phosphorus inner salt as a reagent is mild, the production yield is high, and the application is wide.
1 citations
TL;DR: In this article, the Wittig reaction of aldehydes with difluoromethyltriphenylphosphonium bromide leading to gem-difluorsoolefins in moderate yields is described.
Abstract: Wittig reaction of aldehydes with difluoromethyltriphenylphosphonium bromide leading to gem-difluoroolefins in moderate yields is described. The reaction displays a good substrate scope including aryl, heteroaryl and alpha,beta-unsaturated aldehydes. Difluoromethyltriphenylphosphonium bromide could be easily prepared and stored for a long time under air atmosphere. The salt exhibits high thermal stability demonstrated by thermogravimetric analysis. Its structure was confirmed by NMR spectroscopy and single crystal X-ray analysis. (C) 2014 Elsevier B.V. All rights reserved.