2425-74-3Relevant articles and documents
A NICKEL-CARBENE COMPLEX AS AN INTERMEDIATE IN THE POLYMERIZATION OF ISOCYANIDES
Kamer, Paul C. J.,Nolte, Roeland, J. M.,Drenth, Wiendelt
, p. 175 - 181 (1988)
An intermediate in the polymerization of isocyanides, catalysed by nickel(II), has been isolated and characterized.The polymerazation starts by nucleophilic attack of (S)-(-)-(1-phenylethyl)amine on the terminal carbon atom of a coordinated isocyanide of tetrakis(tert-butyl isocyanide)nickel(II) perchlorate.The resulting intermediate was isolated and shownto be a nickel-carbene complex: Ni(C=N-t-C4H9)3NH-t-C4H9>(ClO4)2>.In solution, the carbene complex appears to have three conformations.The effect of these conformations on the enantioselective polymerazation of isocyanides is discussed.
Enantioselective Synthesis of Azetidines through [3 + 1]-Cycloaddition of Donor-Acceptor Aziridines with Isocyanides
Zhang, Fengcai,Sang, Xinpeng,Zhou, Yuqiao,Cao, Weidi,Feng, Xiaoming
supporting information, p. 1513 - 1517 (2022/03/01)
The enantioselective [3 + 1]-cycloaddition of racemic donor-acceptor (D-A) aziridines with isocyanides was first realized under mild reaction conditions using a chiral N,N′-dioxide/MgIIcomplex as catalyst, providing a facile route to enantioenriched exo-imido azetidines with good to excellent yield (up to 99%) and enantioselectivity (up to 94% ee). An obvious chiral amplification effect was observed in this system, and an explanation was elucidated based on the experimental investigation and X-ray crystal structure of the enantiomerically pure catalyst.
Selective formylation or methylation of amines using carbon dioxide catalysed by a rhodium perimidine-based NHC complex
Lam, Raphael H.,McQueen, Caitlin M. A.,Pernik, Indrek,McBurney, Roy T.,Hill, Anthony F.,Messerle, Barbara A.
supporting information, p. 538 - 549 (2019/02/14)
Carbon dioxide can play a vital role as a sustainable feedstock for chemical synthesis. To be viable, the employed protocol should be as mild as possible. Herein we report a methodology to incorporate CO2 into primary, secondary, aromatic or alkyl amines catalysed by a Rh(i) complex bearing a perimidine-based NHC/phosphine pincer ligand. The periminide-based ligand belongs to a class of 6-membered NHC ligand accessed through chelate-assisted double C-H activation. N-Formylation and -methylation of amines were performed using a balloon of CO2, and phenylsilane as the reducing agent. Product selectivity between formylated and methylated products was tuned by changing the solvent, reaction temperature and the quantity of phenylsilane used. Medium to excellent conversions, as well as tolerance to a range of functional groups, were achieved. Stoichiometric reactions with reactants employed in catalysis and time course studies suggested that formylation and methylation reactions of interest begin with hydrosilylation of CO2 followed by reaction with amine substrates.
Polymer Meets Frustrated Lewis Pair: Second-Generation CO2-Responsive Nanosystem for Sustainable CO2 Conversion
Chen, Liang,Liu, Renjie,Yan, Qiang
supporting information, p. 9336 - 9340 (2018/07/25)
Frustrated Lewis pairs (FLP), a couple comprising a sterically encumbered Lewis acid and Lewis base, can offer latent reactivity for activating inert gas molecules. However, their use as a platform for fabricating gas-responsive materials has not yet developed. Merging the FLP concept with polymers, we report a new generation CO2-responsive system, differing from the first-generation ones based on an acid–base equilibrium mechanism. Two complementary Lewis acidic and basic block copolymers, installing bulky borane- and phosphine-containing blocks, were built as the macromolecular FLP. They can bind CO2 to drive micellar formation, in which CO2 as a cross-linker bridges the block chains. This dative bonding endows the assembly with ultrafast response (2 can function as nanocatalysts for recyclable C1 catalysis, opening a new direction of sustainable CO2 conversion.
