82342-65-2Relevant academic research and scientific papers
Novel Syn Oxidative Addition of Allylic Halides to Olefin Complexes of Palladium(0) and Platinum(0)
Kurosawa, Hideo,Kajimaru, Hiroshi,Ogoshi, Sensuke,Yoneda, Hiroto,Miki, Kunio,et al.
, p. 8417 - 8424 (1992)
Stereochemistry of the oxidative addition of 5-(methoxycarbonyl)-2-cyclohexenyl chloride (1a) and bromide (1b) and 5-methyl-2-cyclohexenyl chloride (1c) to palladium(0)-olefin and platinum(0)-olefin complexes to give the corresponding (η3-allyl)palladium and -platinum complexes was examined as a function of solvent and olefin ligands.Novel syn addition (>90percent selectivity) occurred in the reactions of the trans isomers of 1a-c with palladium complexes containing electron-withdrawing olefinic ligands (maleic anhydride, dimethyl fumarate, fumaronitrile, dibenzylideneacetone) carried out in benzene, CH2Cl2, or THF.Somewhat lower syn selectivity (80-43percent) was found in the reactions between these palladium complexes and the cis isomer of 1a or between the analogous platinum complexes and 1a-trans under the same conditions.Anti oxidative addition dominated in the reactions of 1a-trans with electron-withdrawing olefin-palladium complexes in acetonitrile or DMSO, or with electron-donating olefin-palladium complexes in benzene or CH2Cl2.The crystal structure of Pd(trans-(5-methoxycarbonyl)(1-3-η)-cyclohexenyl)(Cl)(PPh3) was determined.Crystal data: C26H26O2ClPPd, fw = 543.32, monoclinic, space group P21/n, a = 12.717 (2) Angstroem, b = 9.881 (2) Angstroem, c = 19.772 (3) Angstroem, β = 105.38 (2) deg, V = 2395.7 (6) Angstroem3, Z = 4, Dc = 1.507 g cm-3, R = 0.043 for 4150 reflections (Fo > 3?(Fo)).The six-membered ring adopts a pseudochair conformation, with COOMe occupying the equatorial position.A reaction path for the syn oxidative addition is proposed with the aid of the relative rates of the oxidative addition observed for a series of methyl-substituted allylic chlorides, ClCHR1CR2=CR3R4.Cross coupling of 1a with RBu3Sn (R = phenyl, vinyl) with net retention of configuration was achieved by the use of a catalyst precursor, 3-C3H5)Cl>2/maleic anhydride.Evidence is given which shows that the catalytic cycle involves two stereoretentive key reactions, namely, oxidative addition of 1a with Pd(0) and reductive elimination of the (η3-allyl)palladiums with organotins, both requiring maleic anhydride as an indispensable ligand to palladium.
Self-assembled poly(imidazole-palladium): Highly active, reusable catalyst at parts per million to parts per billion levels
Yamada, Yoichi M. A.,Sarkar, Shaheen M.,Uozumi, Yasuhiro
supporting information; experimental part, p. 3190 - 3198 (2012/04/10)
Metalloenzymes are essential proteins with vital activity that promote high-efficiency enzymatic reactions. To ensure catalytic activity, stability, and reusability for safe, nontoxic, sustainable chemistry, and green organic synthesis, it is important to develop metalloenzyme-inspired polymer-supported metal catalysts. Here, we present a highly active, reusable, self-assembled catalyst of poly(imidazole-acrylamide) and palladium species inspired by metalloenzymes and apply our convolution methodology to the preparation of polymeric metal catalysts. Thus, a metalloenzyme-inspired polymeric imidazole Pd catalyst (MEPI-Pd) was readily prepared by the coordinative convolution of (NH4)2PdCl4 and poly[(N-vinylimidazole)-co-(N- isopropylacrylamide)5] in a methanol-water solution at 80 °C for 30 min. SEM observation revealed that MEPI-Pd has a globular-aggregated, self-assembled structure. TEM observation and XPS and EDX analyses indicated that PdCl2 and Pd(0) nanoparticles were uniformly dispersed in MEPI-Pd. MEPI-Pd was utilized for the allylic arylation/alkenylation/vinylation of allylic esters and carbonates with aryl/alkenylboronic acids, vinylboronic acid esters, and tetraaryl borates. Even 0.8-40 mol ppm Pd of MEPI-Pd efficiently promoted allylic arylation/alkenylation/vinylation in alcohol and/or water with a catalytic turnover number (TON) of 20 000-1 250 000. Furthermore, MEPI-Pd efficiently promoted the Suzuki-Miyaura reaction of a variety of inactivated aryl chlorides as well as aryl bromides and iodides in water with a TON of up to 3 570 000. MEPI-Pd was reused for the allylic arylation and Suzuki-Miyaura reaction of an aryl chloride without loss of catalytic activity.
A highly active and reusable self-assembled poly(imidazole/palladium) catalyst: Allylic arylation/alkenylation
Sarkar, Shaheen M.,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
supporting information; experimental part, p. 9437 - 9441 (2011/11/06)
Gobs of globules: A polymeric imidazole/acrylamide palladium catalyst, MPPI-Pd (M=PdIICl and Pd0), was utilized for the allylic arylation/alkenylation of allylic esters with aryl/alkenylboronic acids and tetraaryl borates. Low catalyst loadings efficiently promoted the reaction with a catalytic turnover number of 20000-1250000. The catalyst can be reused without loss of catalytic activity.
Zinc borates: Functionalized hard nucleophiles for coupling reactions with secondary allylic acetates
Kobayashi, Yuichi,Tokoro, Yuko,Watatani, Kengo
, p. 3825 - 3834 (2007/10/03)
We have succeeded in developing zinc borates of the general structure 3 for coupling reaction with allylic acetates. The advantages of using compounds 3 are their compatibility with carbonyl groups such as aldehyde, ketone, and ester groups, and their high reactivity toward secondary allylic acetates. Zinc borates 3 were prepared from boronate esters 1 [R(T) = p-(CHO)C6H4, p-(Ac)C6H4, p-{Ac(CH2)2}C6H4, p-(Ac-OCH2)C6H4, p-{AcO(CH2)3}C6H4, p-{EtO2C(CH2}2}C6H4, (E)-CH=CH(CH2)4OAc] with MeZnCl; subsequent treatment with allylic acetates 4 [R = n-C5H11, c-C6H11, (CH2)2CH(-O(CH2}2O-)] in the presence of NiCl2(PPh3)2 (10 mol-%) in THF-DMI (1,3-dimethyl-2-imidazolidinone) (10 equiv.) at 40-50 °C overnight furnished the coupling products 5 in good yields. Among the products, 5bb, possessing one free and one protected aldehyde group, is a highlight of this type of reaction. The stereochemical aspects of the reaction were also examined. Thus, the alkenyl groups of (E)- and (Z)-alkenyl borates 3b and c were transformed with retention of the olefinic geometry into acetates 4a and b (R = n-C5H11, c-C6H11), while reaction of cyclic acetate 11 proceeded with inversion at the carbon center involved in the reaction. In addition, we found that the anions generated from (EtO)2P(= O)CH2CO2Et and (MeO)2P(=O)CH2Ac under Masamune's conditions attacked the aldehyde carbon in the boronate 1d to produce - after reduction of the double bond - the boronate esters 1i and 1j, respectively, in good yields.
Nickel-Catalyzed Coupling Reaction of 1,3-Disubstituted Secondary Allylic Carbonates and Lithium Aryl- and Alkenylborates
Kobayashi, Yuichi,Mizojiri, Ryo,Ikeda, Eitatsu
, p. 5391 - 5399 (2007/10/03)
Tis account describes coupling reaction of 1,3-disubstituted secondary allylic carbonates with lithium aryl- and alkenylborates in the presence of a nickel catalyst.Borates examined are 4, 5, and 6, and reactivity and selectivity were investigated using t
Nickel catalysed coupling of allylamines and boronic acid
Trost, Barry M.,Spagnol, Michel D.
, p. 2083 - 2096 (2007/10/02)
Allylamines function as substrates for cross-coupling with boronic acids in the presence of nickel(0) catalysts rather than palladium(0) catalysts.Aryl-, vinyl- and methyl-boronic acids function well.With vinyl derivatives, E-isomers couple more efficiently than Z-isomer and both fully retain the geometrical integrity.Methylations preferably employ the boronic esters like 2-methyl-1,3,2-benzodioxaborole or 2-methyl-1,3,2-dioxaborolane rather than methylboronic acid.The stereochemistry of the reaction involves a net inversion with respect to the allylamine.The regioselectivity is a function of ligand.Generally, sterically bulky donor phosphines promote new C-C bond formation at the less substituted position.Bidentate ligands, notably 1,1'-binaphthyl-2,2'-ylbis(diphenylphosphinite) (BINAPO), promote new C-C bond formation at the more substituted allyl terminus.The amines appear to be the preferred partner compared to allyl alcohols and esters with the boronic acids and give higher stereospecificity.
Palladium-Catalyzed Coupling of Allylic Acetates with Aryl- and Vinylstannanes
Valle, L. Del,Stille, J. K.,Hegedus, L. S.
, p. 3019 - 3023 (2007/10/02)
The palladium-catalyzed reaction of allyl acetates with aryl- and vinyltin reagents gave good yields of cross-coupled products.The reaction was mild and tolerant of functionality (CO2R, OH, OSiR3, OMe) in the tin reagent.Inversion of stereochemistry at the acetate center was observed, with retention of the geometry of the olefin of the allyl group and with exclusive coupling at the primary position.Retention of geometry of the olefin in the vinyltin reagents was also observed.
PALLADIUM-CATALYZED CROSS COUPLING OF ALLYL HALIDES WITH ORGANOTIN REAGENTS: A METHOD OF JOINING HIGHLY FUNCTIONALIZED PARTNERS REGIOSELECTIVELY AND STEREOSPECIFICALLY.
Sheffy,Godschalx,Stille
, p. 4833 - 4840 (2007/10/11)
The palladium-catalyzed reaction of allyl halides with aryl- and vinyltin reagents gives high yields of cross-coupled products. In the presence of 1-3 atm of carbon monoxide, ketones are obtained, resulting from cross coupling accompanied by carbon monoxide insertion. The reaction is mild and tolerant of a wide variety of functionalities (OH, OR, CN, CO//2R, CHO) on either the allyl chloride or the tin reagent. Coupling at the allyl halide partner proceeds with inversion of configuration at the carbon bearing the halide, with retention of geometry at the allylic double bond, and with a regioselectivity for the least-substituted carbon in the allylic framework. Retention of double-bond geometry is observed in the vinyltin partner.
