40833-04-3Relevant academic research and scientific papers
α-Oxo-Ketenimines from Isocyanides and α-Haloketones: Synthesis and Divergent Reactivity
Mamboury, Mathias,Wang, Qian,Zhu, Jieping
supporting information, p. 12744 - 12748 (2017/09/25)
The palladium-catalyzed reaction of α-haloketones with isocyanides afforded α-oxo-ketenimines through β-hydride elimination of the β-oxo-imidoyl palladium intermediates. Reaction of these relatively stable α-oxo-ketenimines with nucleophiles such as hydrazines, hydrazoic acid, amines, and Grignard reagent afforded pyrazoles, tetrazole, β-keto amidines, and enaminone, respectively, with high chemoselectivity. Whereas amines attack exclusively on the ketenimine functions, the formal [3+2] cycloaddition between N-monosubstituted hydrazines and α-oxo-ketenimines was initiated by nucleophilic addition to the carbonyl group.
Stoichiometric reactions of acylnickel(II) complexes with electrophiles and the catalytic synthesis of ketones
Wotal, Alexander C.,Ribson, Ryan D.,Weix, Daniel J.
, p. 5874 - 5881 (2015/01/09)
Acylnickel(II) complexes feature prominently in cross-electrophile coupling (XEC) reactions that form ketones, yet their reactivity has not been systematically investigated. We present here our studies on the reactivity of acylnickel(II) complexes with a series of carbon electrophiles. Bromobenzene, α-chloroethylbenzene, bromooctane, and iodooctane were reacted with (dtbbpy)NiII(C(O)C5H11)(Br) (1b) and (dtbbpy)NiII(C(O)tolyl)(Br) (1c) to form a variety of organic products. While reactions with bromobenzene formed complex mixtures of ketones, reactions with α-chloroethylbenzene were highly selective for the cross-ketone product. Reactions with iodooctane and bromooctane also produced the cross-ketone product, but in intermediate yield and selectivity. In most cases the presence or absence of a chemical reductant (zinc) had only a small effect on the selectivity of the reaction. The coupling of 1c with iodooctane (60% yield) was translated into a catalytic reaction, the carbonylative coupling of bromoarenes with primary bromoalkanes (six examples, 60% average yield).
Carbonylative coupling of organozinc reagents in the presence and absence of aryl iodides: Synthesis of unsymmetrical and symmetrical ketones
Jackson, Richard F. W.,Turner, Debra,Block, Michael H.
, p. 865 - 870 (2007/10/03)
The utility of the palladium(o) catalysed reaction of the iodoalanine-derived organozinc reagent 6a with functionalised aryl iodides, under a carbon monoxide atmosphere, to give protected 4-aryl-4-oxo α-amino acids 8, is illustrated by a short synthesis of L-kynurenine 4. Treatment of functionalised organozinc reagents with catalytic tetrakis(triphenylphosphine)palladium(0) under an atmosphere of carbon monoxide in the absence of any electrophile leads to the formation of symmetrical functionalised ketones 9 in good yields. This reaction is illustrated by a one-step synthesis of protected (2S,6S)-4-oxo-2,6-diaminopimelic acid 9a from commercially available compounds. It has been established that adventitious molecular oxygen plays a key role in the formation of the symmetrical ketones 9, and that rigorous exclusion of oxygen can result in substantially higher yields of ketones 8 in the cross-coupling with some aromatic iodides.
Preparation of polyfunctional ketones by a cobalt(II) mediated carbonylation of organozinc reagents
Devasagayaraj,Knochel
, p. 8411 - 8414 (2007/10/02)
Functionalized organozinc halides can be efficiently carbonylated under atmospheric pressure in the presence of cobalt(II) bromide in THF:NMP leading to polyfunctional symmetrical ketones in 56-80% yield.
Unsymmetrical Ketone Synthesis via a Three-Component Connection Reaction of Organozincs, Allylating Agents, and Carbon Monoxide
Yasui, Kengo,Fugami, Keigo,Tanaka, Shuji,Tamaru, Yoshinao
, p. 1365 - 1380 (2007/10/02)
A wide variety of organozincs (diethylzinc, alkylzinc halides, and organozincs 2, 5, and 9a-e, functionalized with ester and nitrile groups) undergo a three-component connection reaction with carbon monoxide and allylic benzoates or phosphates 1a-h to furnish unsymmetrical ketones, e.g., 3, 6, and 10, in good yields uder 1 atm of carbon monoxide at ambient temperature by the catalysis of tetrakis(triphenylphosphine)palladium in THF/HMPA.The regio- and stereoselectivities of the present carbonylation show marked contrast to those reported for the palladium-catalyzed carbonylation of usymmetrical allylic substrates.For example, the reaction of crotyl benzoate with octylzinc iodide provides all the possible stereo- and regioisomers, i.e., cis- and trans-2-butenyl and 1-methyl-2-propenyl octyl ketones in comparable amounts.The carbonylative coupling of carvyl phosphates, trans- and cis-1h, and γ-zincio ester 5 is stereospecific and proceeds with inversion of configuration at the allylic stereocenters to furnish cis- and trans-6h, respectively, as single diastereomers.In the absence of HMPA, the reaction feature changes dramatically and lactones 12 and 13 (composed of organozincs, carbon monoxide, and allylating agents in the ratios of 1:1:2 and 2:1:1, respectively) and symmetrical keto diesters 14 (composed of 2 mol of organozincs and 1 mol of carbon monoxide) are formed in varying ratios depending on the reaction conditions.Synthetic scope of the unsymmetrical ketones and mechanistic rationale for these unique and unprecedented reaction behaviors are discussed.
Asymmetric Synthesis of Chiral Spiroacetals from Chiral Diketodisulfoxides: 2,8-dimethyl-1,7-dioxaspiro undecane
Solladie, Guy,Huser, Nathalie
, p. 255 - 260 (2007/10/02)
(2R,6S,8R) and (2S,6R,8S) 2,8-dimethyl-1,7-dioxaspiro undecane have been prepared by asymmetric reduction of a diketodisulfoxide intermediate.
