16640-68-9Relevant articles and documents
-
McClure
, p. 2407 (1967)
-
Selective Construction of C?C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
Liu, Xin,Werner, Thomas
supporting information, p. 1096 - 1104 (2020/12/31)
Herein, we report the manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon-carbon single (C?C) and carbon-carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C?C vs. C=C bonds can be controlled by the reaction conditions, namely the amount of base. The scope and limitations of the coupling reactions were thoroughly evaluated by the conversion of 21 alcohols and 15 ylides. Notably, compared to existing methods, which are based on precious metal complexes as catalysts, the present catalytic system is based on earth abundant manganese catalysts. The reaction can also be performed in a sequential one-pot reaction generating the phosphorus ylide in situ followed manganese catalyzed C?C and C=C bond formation. Mechanistic studies suggest that the C?C bond was generated via a borrowing hydrogen pathway and the C=C bond formation followed an acceptorless dehydrogenative coupling pathway. (Figure presented.).
Synthesis, Purification, and Rotational Spectroscopy of (Cyanomethylene)Cyclopropane—An Isomer of Pyridine
Esselman, Brian J.,Kougias, Samuel M.,Zdanovskaia, Maria A.,Woods, R. Claude,McMahon, Robert J.
, p. 5601 - 5614 (2021/07/20)
The gas-phase rotational spectrum of (cyanomethylene)cyclopropane, (CH2)2C═CHCN, generated by a Wittig reaction between the hemiketal of cyclopropanone and (cyanomethylene)triphenylphosphorane, is presented for the first time. This small, highly polar nitrile is a cyclopropyl-containing structural isomer of pyridine. The rotational spectra of the ground state and two vibrationally excited states were observed, analyzed, and least-squares fit from 130 to 360 GHz. Over 3900 R-, P-, and Q-branch, ground-state rotational transitions were fit to low-error, partial octic, A- and S-reduced Hamiltonians, providing precise determinations of the spectroscopic constants. The two lowest-energy vibrationally excited states, ν17and ν27, form a Coriolis-coupled dyad displaying smalla- andb-type resonances. Transitions for these two states were measured and least-squares fit to a two-state, partial octic, A-reduced Hamiltonian in the Irrepresentation with nine Coriolis-coupling terms (Ga,GaJ,GaK,GaJJ,Fbc,FbcJ,FbcK,Gb, andGbJ). The observation of many resonant transitions and nine nominal interstate transitions enabled a very accurate and precise energy difference between ν17and ν27to be determined: ΔE17,27= 29.8975453 (33) cm-1. The spectroscopic constants presented herein provide the foundation for future astronomical searches for (cyanomethylene)cyclopropane.
Isolation of the Metalated Ylides [Ph3P?C?CN]M (M=Li, Na, K): Influence of the Metal Ion on the Structure and Bonding Situation
Schwarz, Christopher,Scharf, Lennart T.,Scherpf, Thorsten,Weismann, Julia,Gessner, Viktoria H.
supporting information, p. 2793 - 2802 (2019/02/07)
The isolation and structural characterization of the cyanido-substituted metalated ylides [Ph3P?C?CN]M (1-M; M=Li, Na, K) are reported with lithium, sodium, and potassium as metal cations. In the solid-state, most different aggregates could be determined depending on the metal and additional Lewis bases. The crown-ether complexes of sodium (1-Na) and potassium (1-K) exhibited different structures, with sodium preferring coordination to the nitrogen end, whereas potassium binds in an unusual η2-coordination mode to the two central carbon atoms. The formation of the yldiide was accompanied by structural changes leading to shorter C?C and longer C?N bonds. This could be attributed to the delocalization of the free electron pairs at the carbon atom into the antibonding orbitals of the CN moiety, which was confirmed by IR spectroscopy and computational studies. Detailed density functional theory calculations show that the changes in the structure and the bonding situation were most pronounced in the lithium compounds due to the higher covalency.