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1.
Sally Dixon 《Tetrahedron》2004,60(6):1401-1416
A wide range of carbenoids (1-lithio-1-halo species), including those with α-SiR3, OEt, SPh, SO2Ph, P(O)(OEt)2, and CN substituents, insert into 5-member zirconacycles (saturated and unsaturated, mono- and bi-cyclic) to afford functionalized 6-member zirconacycles. 1-Lithio-1-haloalkenes insert to afford 6-member zirconacycles with an alkylidene substituent next to the metal. Unexpected double insertion of some carbenoids, and evidence for endocylic β-hydride transfer processes provide additional mechanistic interest. 相似文献
2.
Fabiano Molinos de Andrade Clovis Peppe Werner Uhl 《Journal of organometallic chemistry》2005,690(5):1294-1299
The reaction of bromomethyl-dibromo-indium(III), Br2InCH2Br with dialkylselenides, R1SeR2 (R1 = CH3, R2 = CH2C6H5; R1 = C2H5, R2 = CH2C6H5; R1 = R2 = CH2C6H5) afforded the corresponding dialkylselenonium methylide complexes of indium tribromide, Br3InCH2SeR1R2, which were fully characterized by NMR spectroscopy and single crystal X-ray diffraction studies. 相似文献
3.
Andrew L. Sargent Mark E. Rollog Cassandra T. Eagle 《Theoretical chemistry accounts》1997,97(1-4):283-288
Fenske-Hall molecular orbital calculations have been applied to a new, structurally isolable analog of the intermediate involved
in catalytic rhodium carboxylate carbenoid transformations. Results from the structural characterization of axially ligated
rhodium acetate phenylisonitrile complexes have been utilized in approximate molecular orbital calculations. The results from
the calculations suggest that a significant degree of π back-bonding exists between the metal and isonitrile fragments which,
by analogy, implies that π back-bonding should also exist in the rhodium carbenoid intermediate. Sensitivity of the Fenske-Hall
method to the magnitude of π back-donation in these complexes was gauged through calculations involving different phenylisonitrile
groups in which the π back-bonding ability was modulated through derivativization. The reliability of the Fenske-Hall method
was evaluated through a comparison to a high-level calculation.
Received: 13 December 1996 / Accepted: 18 March 1997 相似文献
4.
Tandem carbonyl ylide formation-1,3-dipolar cycloaddition of α-diazo N-acetyl-tetrahydro-β-carbolin-1-one derivatives occur efficiently in the presence of a dirhodium catalyst to afford bimolecular cycloadducts in high yield. The Rh(II)-catalyzed reaction also takes place intramolecularly to give products derived from trapping of the carbonyl ylide dipole with a tethered alkene. The power of the intramolecular cascade sequence is that it rapidly assembles a pentacyclic ring system containing three new stereocenters and two adjacent quaternary centers stereospecifically in a single step and in high yield. 相似文献
5.
S. V. Pasenok N. V. Kirij Yu. L. Yagupolskii D. Naumann W. Tyrra A. Fitzner 《无机化学与普通化学杂志》1999,625(5):834-838
The reactions of Zn(CF3)Br · 2 CH3CN, Cd(CF3)2 · 2 CH3CN or Bi(CF3)3/AlCl3 with tertiary amines lead to the formation of quaternary ammonium salts of the general formula [R3NCF2H]X. The reaction of 4‐N,N‐dimethylaminopyridine with Zn(CF3)Br · 2 CH3CN yields (N‐difluoromethyl)‐4‐N,N‐dimethylaminopyridinium bromide. Bi(CF3)3/AlCl3 reacts with 1,4‐diazabicyclo[2.2.2]octane to form a mixture of mono‐ and bis(difluoromethylammonium) salts. 相似文献
6.
IntroductionThe greatsynthetic utility of organolithium reagents has been extended by the introduc-tion ofα-lithium-etherreagents[1— 4] .Those reagentsareeasily prepared,and they can be usedas anionic resources to synthesize a large variety of compounds stereo-selectively[5— 8] .Fur-thermore,such reagents can react with nucleophiles like RLi,only a typical reaction of car-benoid[9,1 0 ] .Though the ambidentnature isof greatinterest,only a little work has been doneon model molecule Li CH2 … 相似文献
7.
Shaozhong Wang 《Tetrahedron letters》2018,59(14):1317-1327
Propargylic carboxylates, as a type of easily available alkyne compounds, have attracted considerable attentions in recent decade. Under the catalysis of transition metal complex (Pd, Ru, Pt, Au, Rh etc), one of chemical transformations of propargylic carboxylate is 1,2-acyloxy migration. The resultant alkenyl metallocarbenoid or metal-containing species may undergo a variety of chemical transformations, leading to formation of carbocyclic and heterocyclic compounds. In this review, representative domino reactions initiated by 1,2-acyloxy migration of propargylic carboxylates are summarized, including pentannuations, cycloadditions and rearrangements. Some mechanistic discussions and synthetic applications are also included. 相似文献
8.
Zhu-Jun Yu Chen Zhang Jiang-Lian Li Yan-Zhao Liu Xin-Ling Yu Li Guo Guo-Bo Li Yong Wu 《Tetrahedron letters》2018,59(29):2816-2819
A mild and efficient procedure was developed for the [Cp1Rh(III)]-catalyzed, 1,2,3-triazole directed CH coupling with diazomethylene-diphosphonates. This protocol provided a step- and atom-economical protocol for CC bond formation and led to structurally diverse 2-(1,2,3-triazol-2-yl)benzyl diphosphonates in good to excellent yields. 相似文献
9.
An operationally simple, economical and straightforward synthesis of diverse oxazoles from oximes possessing a vicinal carbonyl group has been achieved by treatment of the latter with terminal diazo compounds like ethyl/benzyl diazoacetate and diazoacetophenone (which act as carbenoids) in one pot. At least two reducible functional groups (two ester groups or cyano?+?ester) are simultaneously introduced in one step. This reaction involves expulsion of a molecule each of N2 and water only as byproducts under copper catalysis. The structure of one of these oxazoles is confirmed by X-ray crystallography. Both the ester groups in the oxazole product could be reduced to alcohol moieties by using NaBH4/EtOH. 相似文献
10.
Total syntheses of (+)-norsecurinine and (+)-allonorsecurinine are described that utilize a rhodium carbenoid-initiated O-H insertion/Claisen rearrangement/1,2-allyl migration domino process for the stereoselective introduction of the tertiary alcohol moiety. Overall the employed strategy is flexible and will allow access to other members of the Securinega family of alkaloids. 相似文献