18321-36-3Relevant academic research and scientific papers
Stereo and regioselectivity in the phenylation of cationic allylpalladium(II) α-diimine complexes by tetraphenylborate anion
Crociani, Bruno,Antonaroli, Simonetta,Bianca, Francesca Di,Fontana, Alberta
, p. 21 - 26 (1993)
The reaction of the cationic complex 3-cyclohexenyl>(py-2-CH=NC6H4OMe-4)>+ (1) with BPh4- in the presence of fumaronitrile yields trans-3-methoxy-6-phenylcyclohexene (2a) and trans-4-methoxy-3-phenyl-cycohexene (2b), in ca. 1:1 molar ratio.The trans stereochemistry of these products implies that the phenylation of the allyl ligand involves prior transfer of a phenyl group from BPh4- to the metal, followed by reductive coupling of the organic moieties.In the reaction of 3-1,1-R1,R2-C3H3)(N-N')>+ (3) 1 = H, R2 = Ph, Me; R1 = R2 = Me> with BPh4- in the presence of activated olefins, both regioisomers PhCH2-CH=CR1R2 (4a) and CH2=CH-CR1R2Ph (4b) are formed with a relative ratio which depends essentially on the allylic substituents: R1 = H, R2 = Ph, 4a above 98percent; R1 = H, R2 = Me, 4a 75-67percent; R1 = R2 = Me, 4a 64-58percent.The regioisomer distribution is very little affected by the nature of the α-diimine, of the activated olefin, and of the solvent.For R1 = H and R2 = Ph, Me, the olefinic product 4a has a trans (E) geometry.These results have been interpreted in terms of reductive elimination occurring in the intermediate 3-1,1,R1,R2C3H3)(N-N')> with a ?-N monodentate α-diimine ligand.
Syntheses of Molybdenum(VI) Imido Alkylidene Complexes That Contain a Bidentate Dithiolate Ligand
Tafazolian, Hosein,Tsay, Charlene,Schrock, Richard R.,Müller, Peter
, p. 4024 - 4030 (2018)
Zn(DCTC) (DCTC = 3,6-dichlorodithiacatecholate) reacts with Mo(NAd)(CHCMe2Ph)Cl2(PPh2Me) (Ad = 1-adamantyl) to give Mo(NAd)(CHCMe2Ph)(DCTC)(PPh2Me). The reactions between Zn(DCTC) and Mo(NAd)(CH-t-Bu)(OTf)2(dme) or Mo(NAr)(CHCMe2Ph)(OTf)2(dme) (Ar = 2,6-i-Pr2C6H3; OTf = triflate; dme = 1,2-dimethoxyethane) produce [Mo(NAd)(CH-t-Bu)(DCTC)]2 and [Mo(NAr)(CHCMe2Ph)(DCTC)]2, respectively. Complexes that contain a 3,3′,5,5′-tetrasubstituted dithiabiphenolate were prepared in a reaction between Mo(NAr)(CHCMe2Ph)(Me2pyr)2 (Me2pyr = 2,5-dimethylpyrrolide) and the 3,3′,5,5′-tetrasubstituted dithiabiphenols, (3,3′,5,5′-tetrachlorodithiabiphenol (H2Cl4S2), 3,3′,5,5′-tetrabromodithiabiphenol (H2Br4S2), and 3,3′,5,5′-tetra-t-Bu-dithiabiphenol (H2Bu4S2)). The isolated complexes include Mo(NAr)(CHCMe2Ph)(Cl4S2)(pyridine), Mo(NAr)(CHCMe2Ph)(Br4S2)(pyridine), Mo(NAr)(CHCMe2Ph)(Bu4S2)(PMe3), and [Mo(NAr)(CHCMe2Ph)(Cl4S2)]2. Only the dithiabiphenolate derivatives (in the presence of B(C6F5)3) show activity for the metathesis of 1-decene, and although that reaction is limited by a sensitivity of the alkylidene complexes to ethylene, as suggested by the reaction between ethylene and Mo(NAr)(CHCMe2Ph)(Bu4S2) to give the ethylene complex, Mo(NAr)(C2H4)(Bu4S2). Mo(NAr)(C2H4)(Bu4S2) was unstable with respect to loss of ethylene and formation of an ethylene-free dimer. Mo(NAd)(CHCMe2Ph)(DCTC)(PPh2Me), [Mo(NAr)(CHCMe2Ph)(DCTC)]2, and [Mo(NAr)(CHCMe2Ph)(Cl4S2)]2 were characterized crystallographically.
Mode attack of atomic carbon on benzene rings
Armstrong, Brian M.
, p. 6007 - 6011 (1998)
Reaction of are generated carbon atoms with tert-butylbenzene, 4, gives 3-methyl-3-phenyl-1-butene, 5, and 1,1-dimethylindane, 6. Labeling studies and isotope effects demonstrate that 5 results from an insertion into a methyl C-H bond followed by 1,2 hydrogen shift while 6 arises from initial ortho C-H insertion followed by intramolecular insertion into a methyl C-H bend. When fluoroboric acid is added to the 77 K matrix of 4 + C, tert-butyltropylium fluoroborate, 18, is formed. Labeling studies indicate that 18 results from initial insertion of C into meta and para C-H bonds of 4 followed by ring expansion to cycloheptatetraenes which are subsequently protonated. The reaction of C with benzene gives similar results, indicating that initial C-H insertion is the preferred mode of attack of atomic carbon on benzene rings.
Reactivity of mixed organozinc and mixed organocopper reagents: 14. Phosphine-nickel catalyzed aryl-allyl coupling of (n-butyl)(aryl)zincs. Ligand and substrate control on the group selectivity and regioselectivity
Kalkan, Melike,Erdik, Ender
, p. 28 - 36 (2016/06/09)
The group selectivity and regioselectivity in the allylation of mixed (n-butyl)(aryl)zinc reagents in THF depends on the nickel catalyst type and also on nature of the allylic substrate. Allylation of (n-butyl)(phenyl)zinc reagent with alkyl substituted primary allylic chlorides and acetates in the presence of NiCl2(dppf) catalysis affords the phenyl coupling product with γ-selectivity. However, allylation with aryl substituted primary allylic substrates results in both phenyl- and alkyl-coupling products with medium α-selectivity in the presence of NiCl2(dppf) catalysis whereas phenyl coupling product is formed with α-selectivity in the presence of NiCl2(Ph3P)2 catalysis. This new NiCl2(dppf) catalyzed protocol for γ-selective aryl allylation of (n-butyl)(aryl)zinc reagents with alkyl substituted primary allylic chlorides in THF at room temperature provides an atom economic alternative to allylation of (aryl)2Zn reagents. A mechanism for the dependence of group selectivity and regioselectivity of Ni catalyzed allylation of (n-butyl)(aryl)zinc reagents on the catalyst ligand and the substrate was proposed.
Short synthesis of chiral 4-substituted (S)-imidazolinium salts bearing sulfonates and their use in γ-selective reactions of allylic halides with grignard reagents
Latham, Christopher M.,Blake, Alexander J.,Lewis, William,Lawrence, Matthew,Woodward, Simon
supporting information; experimental part, p. 699 - 707 (2012/03/11)
A one-pot reaction of Boc-protected amino alcohols and 2-sulfobenzoic anhydride followed by the addition of a wide variety of primary amines has allowed rapid access to diverse libraries of amidosulfonates 1,2-C 6H4(SO3su
Catalyst-free suzuki-type coupling of allylic bromides with arylboronic acids
Scrivanti, Alberto,Beghetto, Valentina,Bertoldini, Matteo,Matteoli, Ugo
supporting information; experimental part, p. 264 - 268 (2012/02/04)
The coupling of arylboronic acids with electron-rich allylic bromides is accomplished in the absence of any transition-metal catalyst through conventional heating. The reaction is completely regioselective, affording only the α-coupled product, and can be carried out under mild aerobic conditions in an organic solvent; the presence of a base is required. Copyright
Understanding the effect of allylic methyls in olefin cross-metathesis
Courchay, Florence C.,Baughman, Travis W.,Wagener, Kenneth B.
, p. 585 - 594 (2007/10/03)
A series of NMR spectroscopy experiments have been conducted with both the model compound, 3-methyl-1-pentene and the corresponding ADMET monomer 3,6,9-trimethylundeca-1,10-diene (11) to better understand the effect of allylic methyls during olefin metath
Heterodimerization of Olefins. 1. Hydrovinylation Reactions of Olefins That Are Amenable to Asymmetric Catalysis
RajanBabu,Nomura, Nobuyoshi,Jin, Jian,Nandi, Malay,Park, Haengsoon,Sun, Xiufeng
, p. 8431 - 8446 (2007/10/03)
Through a systematic examination of ligand and counterion effects, new protocols for a nearly quantitative and highly selective codimerization of ethylene and various functionalized vinylarenes have been discovered. In a typical reaction, 4-bromostyrene and ethylene undergo codimerization in the presence of 0.0035 equiv each of [(allyl)NiBr]2, triphenylphosphine, and AgOTf in CH2Cl2 at -56 °C to give 3-(4-bromophenyl) -1-butene in >98% yield and selectivity. Corresponding reactions with [(allyl)PdX]2 are much less efficient and less selective and may require further optimization before a viable system can be identified. Another useful protocol that gives comparable yield and selectivity involves the use of a single-component catalyst prepared from allyl 2-diphenylphosphinobenzoate, Ni(COD)2, and (C6F5)3B. Recognition of a synergistic relationship between a chiral hemilabile ligand (for example, (R)-2-methoxy-2′-diphenylphosphino-1,1′-binaphthyl, MOP) and a highly dissociated counteranion (BARF or SbF6) in an enantioselective version of the Ni-catalyzed reaction raises the prospects of developing a practical route for the synthesis of 3-arylbutenes. Several pharmaceutically relevant compounds, including widely used 2-arylpropionic acids, can be synthesized from these key intermediates. This reaction appears to be quite general. Synthesis of several new 2-diphenylphosphino-1,1-binaphthyl derivatives, prepared to probe the effect of hemilabile coordination on the efficiency and selectivity of the reaction, are also described.
Zirconium-mediated conversion of homoallylic ethers into cyclopropane derivatives
Gandon, Vincent,Laroche, Christophe,Szymoniak, Jan
, p. 4827 - 4829 (2007/10/03)
Homoallylic ethers react with Cp2ZrCl2/2 n-BuLi reagent to afford cyclopropane derivatives. Cyclopropylcarbinyl-homoallyl rearrangements involving zirconium species are observed depending on the substrate structure.
Nickel catalyzed hydrovinylation of arylethylenes: General method of synthesis of α-arylpropionic acids intermediates
Fassina, Viviane,Ramminger, Carolina,Seferin, Marcus,Monteiro, Adriano L
, p. 7403 - 7409 (2007/10/03)
The hydrovinylation of arylethylenes catalyzed by [Ni(MeCN)6][BF4]2/AlEt2Cl/PPh3 was modulated to obtain 3-aryl-1-butenes in high yields and selectivities. A wide variety of arylethylenes containing electron-donating or electron-withdrawing groups and Lewis basic group, can be hydrovinylated at room temperature and under mild conditions by changing the relative ratios of the three-component catalyst. Similar activities and selectivities were observed for o-, m- and p-substituted styrenes. Also, the hydrovinylation of olefins with substituents in the vinyl fragment, such as α-methylstyrene and indene, can be accomplished. (C) 2000 Elsevier Science Ltd.
