- Directed Nickel-Catalyzed Diastereoselective Reductive Difunctionalization of Alkenyl Amines
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We report herein an intermolecular syn-arylalkylation and alkenylalkylation of alkenyl amines with two different organohalides (iodides and bromides) using Ni(II) catalyst. The cleavable bidentate quinolinamide is utilized after extensive directing group screening to enable olefin difunctionalization with high levels of regio-, chemo-, and diastereocontrol. This general and practical protocol is compatible with α- or β-substituted terminal alkenes and internal alkenes, providing rapid access to branched aliphatic amines bearing two skipped and vicinal stereocenters with high diastereoselectivities that would otherwise be difficult to synthesize.
- Zhao, Lei,Meng, Xiao,Zou, Yifeng,Zhao, Junsong,Wang, Lili,Zhang, Lanlan,Wang, Chao
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supporting information
p. 8516 - 8521
(2021/10/25)
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- Rhodium-Catalyzed Diverse Arylation of 2,5-Dihydrofuran: Controllable Divergent Synthesis via Four Pathways
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The rhodium-catalyzed controllable diverse arylation of 2,5-dihydrofuran with arylboronic acids is reported. By fine-tuning of the reaction conditions, four different ring-opening or oxidative arylation pathways are controlled in the rhodium-catalyzed ary
- Dou, Xiaowei,Hayashi, Tamio,Lu, Tao,Xing, Junhao,Ye, Bihai,Zhu, Wanjiang
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p. 2958 - 2963
(2020/03/23)
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- Generation and Application of (Diborylmethyl)zinc(II) Species: Access to Enantioenriched gem-Diborylalkanes by an Asymmetric Allylic Substitution
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We report the successful generation of (diborylmethyl)zinc(II) species by transmetallation beteween isolable (diborylmethyl)lithium and zinc(II) halide (X=Br, Cl) and their application in the synthesis of enantioenriched gem-diborylalkanes bearing a stereogenic center at the β-position of the diboryl groups by an asymmetric allylic substitution reaction. The reaction has a broad substrate scope, and various enantioenriched gem-diborylalkanes can be obtained in good yields with excellent enantioselectivity. Further elaboration of the enantioenriched gem-diborylalkanes provides access to a diverse set of valuable chiral building blocks.
- Lee, Yeosan,Park, Jinyoung,Cho, Seung Hwan
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supporting information
p. 12930 - 12934
(2018/09/25)
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- Nickel-Catalyzed Direct Coupling of Allylic Alcohols with Organoboron Reagents
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The direct coupling of allylic alcohols with arylboronic acids or their derivatives catalyzed by Ni(cod)2 in the presence of a catalytic amount of base has been developed. A wide variety of allylic substrates or arylboronic acids turned out to be applicable to this catalytic system. The present method does not require the use of ligands for stabilizing the nickel catalyst in most cases or additional activators for activation of allylic alcohols.
- Wang, Gaonan,Gan, Yi,Liu, Yuanhong
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supporting information
p. 916 - 920
(2018/09/22)
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- Total Synthesis of (-)-Chanoclavine i and an Oxygen-Substituted Ergoline Derivative
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An efficient and direct route to ergot alkaloid (-)-chanoclavine I (3) is described using the inexpensive compound (2R)-(+)-phenyloxirane (15) as a chiral pool in 13 steps with 17% overall yield. Key features of the synthesis include a palladium-catalyzed intramolecular aminoalkynylation of terminal olefin and a rhodium-catalyzed intramolecular [3 + 2] annulation. An oxygen-substituted ergoline derivative (-)-25 was also achieved by using the same strategy.
- Lu, Jia-Tian,Shi, Zi-Fa,Cao, Xiao-Ping
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supporting information
p. 7774 - 7782
(2017/08/14)
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- Cross-coupling of vinylethylene carbonates with arylboronic acids catalyzed by in situ generated palladium nanoparticles in water
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A practical and greener method of the cross-coupling of vinylethylene carbonates (VECs) with arylboronic acids has been described. The coupling reaction was catalyzed by in situ generated palladium nanoparticles (PdNPs) without any ligands and additional stabilizers in water under ambient conditions to provide useful 4-hydroxylprenylarenes and their derivatives in good to high yields.
- Mao, Yuxue,Zhai, Xing,Khan, Ajmal,Cheng, Jiong,Wu, Xue,Zhang, Yong Jian
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supporting information
p. 3268 - 3271
(2016/07/11)
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- Reversible C-C bond activation enables stereocontrol in Rh-catalyzed carbonylative cycloadditions of aminocyclopropanes
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Upon exposure to neutral or cationic Rh(I)-catalyst systems, amino-substituted cyclopropanes undergo carbonylative cycloaddition with tethered alkenes to provide stereochemically complex N-heterocyclic scaffolds. These processes rely upon the generation and trapping of rhodacyclopentanone intermediates, which arise by regioselective, Cbz-directed insertion of Rh and CO into one of the two proximal aminocyclopropane C-C bonds. For cyclizations using cationic Rh(I)-systems, synthetic and mechanistic studies indicate that rhodacyclopentanone formation is reversible and that the alkene insertion step determines product diastereoselectivity. This regime facilitates high levels of stereocontrol with respect to substituents on the alkene tether. The option of generating rhodacyclopentanones dynamically provides a new facet to a growing area of catalysis and may find use as a (stereo)control strategy in other processes.
- Shaw, Megan H.,McCreanor, Niall G.,Whittingham, William G.,Bower, John F.
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supporting information
p. 463 - 468
(2015/01/30)
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- SnCl2/KI-mediated allylation reactions of formaldehyde in water
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An efficient procedure for SnCl2/KI-mediated allylation reactions of formaldehyde with a variety of allylic bromides in aqueous solution is reported. Under conditions developed in this effort, various homoallylic alcohols and 2-halohomoallylic alcohols are produced in good to excellent yields. Georg Thieme Verlag Stuttgart New York.
- Lin, Mei-Huey,Lin, Long-Zhi,Chuang, Tsung-Hsun
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supporting information; experimental part
p. 1871 - 1874
(2011/09/16)
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- Copper-free defluorinative alkylation of allylic difluorides through Lewis acid-mediated C-F bond activation
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The reactions of difluorohomoallyl alcohols with trialkylaluminiums smoothly proceeded in CH2Cl2 at room temperature to give (Z)-fluoro-olefin products in excellent yields. On the basis of this chemistry, fluoro-olefinic dipeptide isostere of norvalinyl glycine was synthesized in stereoselective manner.
- Yanai, Hikaru,Okada, Haruna,Sato, Azusa,Okada, Midori,Taguchi, Takeo
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supporting information; experimental part
p. 2997 - 3000
(2011/06/21)
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- Catalytic scaffolding ligands: An efficient strategy for directing reactions
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The design and application of a scaffolding ligand that promotes branch and diastereoselective hydroformylation of terminal olefins as well as the regio- and diastereoselective hydroformylation of disubstituted olefins is reported. It is shown that the ligand covalently and reversibly bonds to the substrate, allowing for directed hydroformylation. As the substrate ligand interaction is dynamic, hydroformylations are catalytic in ligand and do not require any additional synthetic steps to add or remove the directing group. Using a catalytic quantity of a scaffolding ligand (20-25 mol %), excellent regioselectivity for disubstituted olefins (up to 98:2) and high branch selectivity (up to 88:12) for terminal olefins were obtained. Copyright
- Lightburn, Thomas E.,Dombrowski, Michael T.,Tan, Kian L.
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supporting information; experimental part
p. 9210 - 9211
(2009/02/03)
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- Single-pot triple catalytic transformations based on coupling of in situ generated allyl boronates with in situ hydrolyzed acetals
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In situ hydrolyzed acetals were coupled with in situ generated allyl boronates in a one-pot procedure, affording regio- and stereodefined homoallyl alcohols, epoxides and amino alcohols. The Royal Society of Chemistry.
- Selander, Nicklas,Szabo, Kalman J.
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supporting information; experimental part
p. 3420 - 3422
(2009/02/05)
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- Palladium-catalyzed Heck arylations of allyl alcohols in ionic liquids: Remarkable base effect on the selectivity
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Pd-catalyzed Heck arylation of allyl alcohols in tetraalkylammonium ionic liquids (ILs) can be made highly selective toward the formation of either aromatic carbonyl compounds or aromatic conjugated alcohols by carefully choosing both the IL and the base.
- Calo, Vincenzo,Nacci, Angelo,Monopoli, Antonio,Ferola, Valentina
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p. 2596 - 2601
(2007/10/03)
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- Rhodium-catalysed substitutive arylation of cis-allylic diols with arylboroxines
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Substitutive arylation of cis-allylic diols occurs upon treatment with arylboroxines in the presence of a rhodium(i) catalyst; the reaction proceeds through the addition of an intermediate arylrhodium(i) species across the carbon-carbon double bond and su
- Miura, Tomoya,Takahashi, Yusuke,Murakami, Masahiro
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p. 595 - 597
(2007/10/03)
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- Reaction of allylic-type diindium compounds with electrophiles
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Allylic-type diindium reagents were prepared from 3-bromo-1-iodopropene (1a), 3-bromo-1-iodo-1-phenylpropene (1b), or 2,4-diiodobut-2-en-1-ol (1c) with metallic indium, and their successive coupling with electrophiles was examined. The coupling behavior o
- Hirashita, Tsunehisa,Arai, Shun,Mitsui, Kazuma,Makino, Hajime,Araki, Shuki
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p. 314 - 315
(2007/10/03)
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- Palladium pincer complex catalyzed cross-coupling of vinyl epoxides and aziridines with organoboronic acids
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Palladium-catalyzed crosscoupling of vinyl epoxides and aziridines with organoboronic acids was performed by using 0.5-2.5 mol % pincer-complex catalyst. The reactions proceed under mild conditions affording allyl alcohols and amines with high regioselectivity and in good to excellent yields. Under the applied reaction conditions aromatic chloro-, bromoand iodo substituents are tolerated. Our results indicate that the mechanism of the pincer complex catalyzed and the corresponding palladium(O) catalyzed process is substantially different. It was concluded that the transformations proceed via transmetalation of the organoboronic acids to the pincercomplex catalyst followed by an S N2′type opening of the vinyl epoxide or aziridine substrate. In this process the palladium atom is kept in oxidation state +2 under the entire catalytic process, and therefore oxidative side reactions can be avoided.
- Kjellgren, Johan,Aydin, Juhanes,Wallner, Olov A.,Saltanova, Irina V.,Szabo, Kalman J.
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p. 5260 - 5268
(2007/10/03)
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- Stereoselective cyclization reactions of IBX-generated alkoxyamidyl radicals
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In this paper, a method for the generation of alkoxyamidyl radicals is presented. These N-centered radicals can efficiently be formed starting from the corresponding acylated alkoxyamines using IBX as an oxidant. Stereoselective 5-exo and 6-exo reactions with these N-heteroatom-centered radicals leading to isoxazolidines and [1,2]oxazinanes are discussed. The N-O bond in the heterocycles can readily be cleaved with SmI2 to provide N-acylated 1,3-amino alcohols.
- Janza, Birgit,Studer, Armido
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p. 6991 - 6994
(2007/10/03)
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- [2,3]-Wittig rearrangement by a chlorine-lithium exchange
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The reaction of different allylic chloromethyl ethers 1 with an excess of lithium powder (1:7 molar ratio) and a catalytic amount of DTBB (2.5 mol %) in THF at 0°C for 1 h gives, after hydrolysis with water, the expected alcohols 2 resulting from a [2,3]-Wittig rearrangement, in an exclusive manner. The same process can also be applied to the corresponding [1,2]-Wittig rearrangement, as it is exemplified for benzyl chloromethyl ether.
- Maciá, Beatriz,Gómez, Cecilia,Yus, Miguel
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p. 6101 - 6104
(2007/10/03)
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- Preparation, structure, and unique thermal [2 + 2], [4 + 2], and [3 + 2] cycloaddition reactions of 4-vinylideneoxazolidin-2-one
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The terminal allene Cα=Cβ bonds of 4-vinylidene-2-oxazolidinone (2) readily undergo [2 + 2] cycloaddition with a wide variety of terminal alkynes, alkenes, and 1,3-dienes irrespective of their electronic nature under strictly thermal activation conditions (70-100°C) and provide 3-substituted (Z)-methylenecyclobutenes 6, 3-substituted methylenecyclobutanes 7 and 8, and 3-vinylmethylenecyclobutanes 9, respectively, in good to excellent yields. Alkenes react with 2 with complete retention of configuration. The [2 + 2] cycloaddition is concluded to proceed via a concerted [(π2s + π2s)allene + π2s] Hueckel transition state on the basis of experimental evidences and quantum mechanical methods. Some highly polarized enones and nitrile oxide, on the other hand, react with 2 selectively at the internal C4=Cα double bonds and give spiro compounds 10 and 11, respectively. The bent allene bonds (173-176°) and the unique reactivity associated with 2 are attributed to a low-lying LUMO (Cα=Cβ) that is substantiated by a through-space σ*(N-SO2)-π*(Cα= Cβ) orbital interaction.
- Horino, Yoshikazu,Kimura, Masanari,Tanaka, Shuji,Okajima, Toshiya,Tamaru, Yoshinao
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p. 2419 - 2438
(2007/10/03)
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- Diastereoselective cycloadditions of chiral homoallylic alcohols with benzonitrile oxide
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The first diastereoselective cycloaddition of a nitrile oxide with a homoallylic alcohol is discussed. The reaction of benzonitrile oxide with the magnesium alkoxides of chiral homoallylic alcohols has been shown to proceed with good diastereoselectivity, favoring the syn isomer of the resulting 2-isoxazoline.
- Kociolek, Martin G.,Hongfa, Chayanant
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p. 1811 - 1813
(2007/10/03)
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- Stereoselective pinacol-type rearrangement of 2,3-epoxy alcohols with retention of configuration mediated by bis(iodozincio)methane
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Retention of the configuration is observed in the pinacol-type rearrangement of 2,3-epoxy alcohols 1 in the presence of bis(iodozincio)methane (2). The 1,3-migration of the hydroxymethyl group affords an intermediate 2-hydroxyaldehyde, which is methylenat
- Matsubara, Seijiro,Yamamoto, Hiromasa,Oshima, Koichiro
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p. 2837 - 2840
(2007/10/03)
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- The Palladium-Catalyzed Cross-Coupling Reaction of Organosilicon Compounds with Allylic Carbonates or Diene Monoxides
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The cross-coupling reaction of allylic carbonates with organosilanes was found to proceed without fluoride ion activation under mild conditions by using a coordinatively unsaturated palladium complex as a catalyst.The reaction was assumed to proceed through an allylpalladium alkoxide derived from the allylic carbonate substrate and a palladium(0) species, the alkoxo ligand activating the organosilicon reagent.Likewise, diene monoxides also underwent cross-coupling with alkenyl- and arylfluorosilanes in moderate to high yields.
- Matsuhashi, Hayao,Asai, Satoshi,Hirabayashi, Kazunori,Hatanaka, Yasuo,Mori, Atsunori,Hiyama, Tamejiro
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p. 1943 - 1952
(2007/10/03)
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- Reaction of α-halo organoindium reagents with carbonyl compounds and electron-deficient alkenes
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A variety of α-halo organoindium reagents were prepared in situ from the reaction of gem-dihalo compounds with indium metal, and their reactions with carbonyl compounds and electron-deficient alkenes were examined. The reactions of simple 1,1-diiodoalkanes with indium metal gave no defined products but benzal iodide gave stilbene in a moderate yield. α-Halo organoindium reagents derived from α,α-dibromo carbonyl compounds gave oxiranes and cyclopropanes upon the reactions with aldehydes and alkenes, respectively. 3,3-Dichloropropenes reacted with aldehydes in the presence of indium metal to give the corresponding chlorohydrins and/or homoallylalcohols, depending on the structures of both the dichloropropenes and aldehydes employed.
- Araki, Shuki,Hirashita, Tsunehisa,Shimizu, Ken,Ikeda, Takahiro,Butsugan, Yasuo
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p. 2803 - 2816
(2007/10/03)
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- Synthesis of six-membered compounds by environmentally friendly cyclization using indirect electrolysis
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[Ni(cyclam)](ClO4)2-catalyzed indirect electroreduction of olefinic bromides produced six-membered compounds in low to high yields. The synthetic intermediate 49 of Ipecac and Corynanthe alkaloids was obtained in 88% yield in a highly stereoselective manner. Lactam 66, the synthetic precursor of tacamonine, was prepared in 49% yield as a mixture of two diastereoisomers. The electrolysis of the bromoacetates gave the debrominated compounds in good yields.
- Ihara, Masataka,Katsumata, Akira,Setsu, Fumihito,Tokunaga, Yuji,Fukumoto, Keiichiro
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p. 677 - 684
(2007/10/03)
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- Stereoselectivity of Intramolecular Cyclisations of Nitrones Derived from 3-Oxahept-6-enals
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Intramolecular cycloadditions of the nitrones 9 and 14 show moderate to good stereoselections in favour of the cis-fused diastereoisomers 10 or 16, respectively.
- Gravestock, Michael B.,Knight, David W.,Lovell, Jennifer S.,Thornton, Steven R.
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p. 1661 - 1664
(2007/10/02)
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- EFFICIENT AND REGIOCONTROLLED NICKEL(II)-CATALYZED ALKYLATION OF 2-ALKYL-1,3-DIOXEP-4-ENES BY GRIGNARD REAGENTS: A SIMPLE ROUTE TO ALLYLIC ALCOHOLS
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The regio- and the stereochemistries of the NidppeCl2 catalyzed alkylation of 2-alkyl-1,3-dioxep-4-enes by Grignard reagents are not affected by the nature of the C2 substituent; in any case, allylic alcohols are the main reaction products and nearly pure Z isomers are almost quantitatively obtained when either secondary or tertiary Grignard reagents are used.A rationale for the reaction is proposed.
- Malanga, Corrado,Menicagli, Rita,Lardicci, Luciano
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- NICKEL(II)-CATALYZED ALKYLATION OF 2-METHYL-1,3-DIOXEP-4-ENE BY GRIGNARD REAGENTS: AN EFFICIENT AND SELECTIVE ROUTE TO ALLYLIC ALCOHOLS
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Allylic alcohols are formed, in good yields, through the regiocontrolled Cl2Nidppe-catalyzed alkylation of 2-methyl-1,3-dioxep-4-ene by Grignard reagents .Highly pure Z alcohols arise when secondary and tertiary aliphatic Grignards are used.
- Menicagli, Rita,Malanga, Corrado,Finato, Barbara,Lardicci, Luciano
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- PALLADIUM CATALYZED COUPLING OF ORGANOSTANNANES WITH VINYL EPOXIDES
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The coupling reaction of organotin reagents with vinyl epoxides, catalyzed by palladium, takes place at ambient temperatures, regioselectively, giving predominately the 1,4-addition product.Both aryl- and vinylstannanes undergo coupling in high yields, wh
- Tueting, David R.,Echavarren, Antonio M.,Stille, J. K.
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p. 979 - 992
(2007/10/02)
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- THIA-ACYLIMINIUM CYCLISATIONS. SYNTHESIS OF FIVE-MEMBERED RINGS AND MACROCYCLES
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Cyclisations of carbinollactams 1b-3b afford macrocycles 4-6 in good yield by the intermediacy of N-acyliminium species.A similar process applied to lactams 21b-25b affords the pyrrolizidine type compounds 26-35 through consecutive azonium-Cope rearrangem
- Hamersma, J. A. M.,Nossin, P. M. M.,Speckamp, W. N.
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p. 1999 - 2006
(2007/10/02)
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- Substitution Reactions of Secondary Halides and Epoxides with Higher Order, Mixed Organocuprates, R2Cu(CN)Li2: Synthetic, Stereochemical, and Mechanistic Aspects
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Higher order cuprates, represented by the general formula R2Cu(CN)Li2, are readily prepared from copper cyanide and 2 equiv of an organolithium.These novel reagents react readily and efficiently with secondary unactivated iodides and bromides affording products of substitution.Likewise, mono-, di-, and trisubstituted epoxides undergo ring opening leading to the corresponding alcohols in excellent yields.The effects of solvent, temperature, gegenion, and variations in ligands are discussed.Replacement of the second equivalent of RLi by CH3Li strongly encouragestransfer of R over CH3 in R(CH3)Cu(CN)Li2 with halides.Use of PhLi as RRLi in place of one RTLi (i.e.RT(Ph)Cu(CN)Li2) is suggested for oxirane cleavage.The stereochemical implications associated with both couplings are also addressed.
- Lipshutz, Bruce H.,Wilhelm, Robert S.,Kozlowski, Joseph A.,Parker, David
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p. 3928 - 3938
(2007/10/02)
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- THE 2-AZA-COPE N-ACYLIMINIUM CYCLIZATION
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The 2-aza-Cope N-acyliminium ring closure is shown to proceed in a stereoselective fashion via the primary N-acyliminium intermediate 1B.The latter ion can also be generated from the open hydroxymethyllactam 6b.
- Ent, Hugo,Koning, Henk de,Speckamp, W. Nico
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p. 2109 - 2112
(2007/10/02)
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- HOMOLYTIC DISPLACEMENT AT CARBON. V. FORMATION OF CYCLOPROPYLCARBINYLSULPHONES AND TRICHLOROETHYLCYCLOPROPANES FROM BUT-3-ENYL COBALOXIMES BY A NOVEL PROCESS INVOLVING HOMOLYTIC ATTACK AT THE δ-CARBON OF THE BUTENYL LIGAND
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But-3-enyl- and substituted but-3-enylcobaloximes react with bromotrichlormethane (or trichloromethanesulphonyl chloride) and with 4-toluenesulphonyl chloride thermally or photochemically to give good yields of β,β,β-trichloroethylcyclopropanes and cyclopropylcarbinyl(tolyl)sulphones, respectively.The reactions proceed by a chain mechanism in which a key step is a novel process in which homolytic attack of a trichloromethyl or 4-toluenesulphonyl radical at the δ-carbon of the butenyl ligand leads to synchronous or subsequent attack of the incipient γ-carbon radical on the α-carbon, causing cyclisation and displacement of cobaloxime(II).The other propagation step involves the reaction of the cobaloxime(II) with the bromotrichloromethane, trichloromethanesulphonyl chloride or 4-toluenesulphonyl chloride to give the reactive organic radical.
- Ashcroft, Martyn R.,Bury, Adrian,Cooksey, Christopher J.,Davies, Alwyn G.,Gupta, B. Dass,et al.
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