Trialkyl Methanetricarboxylate as Dialkyl Malonate Surrogate in Copper-Catalyzed Enantioselective Propargylic Substitution

Huang, Guanxin; Cheng, Cang; Ge, Luo; Guo, Beibei; Zhao, Liang; Wu, Xiaoyu

doi:10.1021/acs.orglett.5b02463

Cited by 38 publications

(13 citation statements)

References 36 publications

(28 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 1 b indicates that electron-rich phosphines are superior to electron-deficient phosphines possibly because electron-rich phosphine can facilitate the cleavage of the propargylic C–O bond when Cu-2 is converted to Cu-3 . Unlike other copper-catalyzed propargylation methods performed in aprotic solvents, 25 − 29 polydentate ligands did not accelerate the reaction in water in this study. Therefore, the copper-catalyzed propargylic C–O bond cleavage in water requires different ligand design principles.…”

Section: Results and Discussioncontrasting

confidence: 76%

Using Ligand-Accelerated Catalysis to Repurpose Fluorogenic Reactions for Platinum or Copper

et al. 2020

View full text Add to dashboard Cite

The development of a fluorescent probe for a specific metal has required exquisite design, synthesis, and optimization of fluorogenic molecules endowed with chelating moieties with heteroatoms. These probes are generally chelation- or reactivity-based. Catalysis-based fluorescent probes have the potential to be more sensitive; however, catalytic methods with a biocompatible fluorescence turn-on switch are rare. Here, we have exploited ligand-accelerated metal catalysis to repurpose known fluorescent probes for different metals, a new approach in probe development. We used the cleavage of allylic and propargylic ethers as platforms that were previously designed for palladium. After a single experiment that combinatorially examined >800 reactions with two variables (metal and ligand) for each ether, we discovered a platinum- or copper-selective method with the ligand effect of specific phosphines. Both metal–ligand systems were previously unknown and afforded strong signals owing to catalytic turnover. The fluorometric technologies were applied to geological, pharmaceutical, serum, and live cell samples and were used to discover that platinum accumulates in lysosomes in cisplatin-resistant cells in a manner that appears to be independent of copper distribution. The use of ligand-accelerated catalysis may present a new blueprint for engineering metal selectivity in probe development.

show abstract

Section: Results and Discussioncontrasting

confidence: 76%

Using Ligand-Accelerated Catalysis to Repurpose Fluorogenic Reactions for Platinum or Copper

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The success of copper-Pybox complexes for enantioselective propargylic substitution reactions prompted Wu and co-workers in the year 2015 for the rst time developed enantioselective propargylation of trialkyl methane tricarboxylate 159 with propargylic alcohol derivatives 158, using pybox ligand 160, Scheme 70. 101 The reaction proceeded via the formation of copper allenylidene complexes as key intermediates following the attack of the trialkyl methane tricarboxylate. The temperature shi from room temperature to 0 C drastically improved the enantioselectivity from 31% ee to 68% ee.…”

Section: Copper Derived Catalystsmentioning

confidence: 99%

Scope and advances in the catalytic propargylic substitution reaction

2018

View full text Add to dashboard Cite

show abstract

“…In practice however, it is not clear how rigorously these good‐practice procedures should be implemented. Indeed, in contrast to the benzyl and monoester enolate carbanions involved in the anionic polymerization of styrenes and (meth)acrylates, respectively, CH 2 C(COOR) 2 (−) malonate carbanions do not react with CO 2 under normal conditions, the formed adduct CH 2 C(COOR) 2 COO (−) being thermodynamically unstable . Likewise, proton transfer to water should not thermodynamically occur in solvents such as DMSO (p K a (H 2 O in DMSO) = 31.4, p K a (Et‐CH(COOMe) 2 = 18.5) .…”

Section: Resultsmentioning

confidence: 99%

“…FT purge VN purge Glovebox [19,20] Likewise, proton transfer to water should not thermodynamically occur in solvents such as DMSO (pK a (H 2 O in DMSO) = 31.4, pK a (EtCH(COOMe) 2 = 18.5). [21,22] Con versely, authors have indicated that malonate carbanions highly diluted in DMSO disappear over time at room tem perature, although the nature of the reaction has never been established.…”

Section: Design Of a Minimal Set Of Polymerization Conditionsmentioning

confidence: 99%

Design of Optimized Reaction Conditions for the Efficient Living Anionic Polymerization of Cyclopropane‐1,1‐Dicarboxylates

Benlahouès

Brissault

Boileau

et al. 2017

Macro Chemistry & Physics

View full text Add to dashboard Cite

was also offered, opening an access route to a large family of laterally functionalized poly mers (for example, poly(1) in Scheme 1). In addition, high temperatures, up to 120-140 °C, can be used and further modi fications of the obtained macrocarbanion with electrophiles are possible due to the excellent thermal stability and wellknown nucleophilicity of malonate carbanions, the propagating species involved in these polymerizations. [3,7,14] The prototypical monomers that have been efficiently polymerized thus far in this series of activated cyclopropanes are based on cyclopropyl rings 1 geminally substituted by two electronwithdrawing groups, typically esters (Scheme 1) but also nitriles. Monomers with two propyl ester groups (either as n or ipropyl) have been particularly investigated, as both the monomers and their homopolymers are soluble in a wide variety of solvents, in contrast to methyl or ethyl ester polymers whose solubility in organic solvents com patible with mandatory anionic polymerization conditions is low, due to their high susceptibility to crystallize.Conditions that have so far been found to polymerize 1 liv ingly can be schematically divided into two sets, depending on the type of counterion associated to the malonate RC(COOR) − carbanion on the growing chain. One set involves simple alkali ions, [1][2][3][4] while the other one implicates the large tBuP 4 H + phosphazenium cation derived from the protonation of tBuP 4 superbase (see Scheme 3 for a mechanism). [6,7] Both systems have their pros and cons. The first one is much cheaper, involves relatively straightforward workup processes, but the polymerization is slow, has to be carried out at high tempera tures (typically over 100 °C), which are not necessarily compat ible with some functional groups on the ester, and is practi cally limited to degrees of polymerization of 20-30. The second one is much faster, with polymerization temperatures usually close to 50-60 °C. As a result, it tolerates a wide variety of ini tiators and functional groups on the monomers, and much higher degrees of polymerization can be targeted. In addition, polymerizations can be carried out in classical solvents such as THF or toluene. The main drawbacks are the high cost of the required, commercially available, tBuP 4 superbase, and the lipophilicity and possible toxicity of the generated tBuP 4 H + phosphazenium ion, [15,16] which can seriously complicate the purification of the obtained polymers/oligomers. Cyclopropane PolymerizationA reinvestigation of the experimental parameters used when polymerizing anionically a cyclopropane-1,1-dicarboxylate indicates that several key steps have to be considered, but that other steps-including some routinely used up to now-although not harmful, are nevertheless useless. A robust protocol is thus designed whose implementation allows us to routinely control the polymerization of di-n-propyl cyclopropane-1,1-dicarboxylate, used as a model monomer for the entire family of cyclopropyl monomers geminally activated by two est...

show abstract

Trialkyl Methanetricarboxylate as Dialkyl Malonate Surrogate in Copper-Catalyzed Enantioselective Propargylic Substitution

Cited by 38 publications

References 36 publications

Using Ligand-Accelerated Catalysis to Repurpose Fluorogenic Reactions for Platinum or Copper

Using Ligand-Accelerated Catalysis to Repurpose Fluorogenic Reactions for Platinum or Copper

Scope and advances in the catalytic propargylic substitution reaction

Design of Optimized Reaction Conditions for the Efficient Living Anionic Polymerization of Cyclopropane‐1,1‐Dicarboxylates

Contact Info

Product

Resources

About