- Benchtop Delivery of Ni(cod)2 using Paraffin Capsules
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A facile method that allows for Ni(cod)2 to be used on the benchtop is reported. The procedure involves the preparation of paraffin-Ni(cod)2 capsules, which are stable to air and moisture. It is demonstrated that these readily available capsules can be used to promote a range of Ni(cod)2-catalyzed transformations. These studies are expected to promote the further use of Ni(cod)2 in organic synthesis.
- Dander, Jacob E.,Weires, Nicholas A.,Garg, Neil K.
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- 3,6-DIAMINO-PYRIDAZIN-3-YL DERIVATIVES, PHARMACEUTICAL COMPOSITIONS CONTAINING THEM AND THEIR USES AS PRO-APOPTOTIC AGENTS
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Compounds of formula (I) wherein Het1, Het2, R1, R2 and R3 are as defined in the description. Medicaments.
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Page/Page column 349-350
(2021/02/05)
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- Highly γ-Regioselective 1,2-Addition of α,β-Unsaturated Oxime Ethers with Allylzinc Bromides: A Straightforward Approach for the Synthesis of Homoallylic Amines
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A highly regioselective reaction between allylzinc bromide reagents and α,β-unsaturated oxime ethers for the one-step synthesis of the homoallylic amines is reported. This process is a regioselective 1,2-addition reaction providing a new γ-position with carbon-carbon bond formation. Furthermore, the reaction substrates are widely applicable and can be produced in a high yield.
- Yang, Bo,Zhang, Songlin
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supporting information
p. 3736 - 3746
(2019/09/30)
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- Direct Reductive N-Functionalization of Aliphatic Nitro Compounds
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The first general protocol for the direct reductive N-functionalization of aliphatic nitro compounds is presented. The nitro group is partially reduced to a nitrenoid, with a mild and readily available combination of B2pin2 and zinc organyls. Thereby, the formation of an unstable nitroso intermediate is avoided, which has so far severely limited reductive transformations of aliphatic nitro compounds. The reaction is concluded by an electrophilic amination of zinc organyls.
- Rauser, Marian,Ascheberg, Christoph,Niggemann, Meike
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supporting information
p. 3970 - 3974
(2018/02/26)
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- O2-Mediated Oxidation of Aminoboranes through 1,2-N Migration
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In analogy to the classical reaction of C?B bonds with peroxides, the first oxidative functionalization of aminoboranes through a 1,2-N migration was realized. Readily available aliphatic nitro compounds are thereby transformed into N- and O-functionalized hydroxylamines in a single synthetic operation. Addition of hazardous peroxides is avoided. Instead, the insertion of O2, as the terminal oxidant, into Zn?C bonds provides the necessary peroxides. The required zinc organyls, in turn, are formed through a boron-to-zinc exchange, from an organoboronic ester byproduct of the nitro-to-aminoborane transformation.
- Rauser, Marian,Warzecha, Daniel P.,Niggemann, Meike
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supporting information
p. 5903 - 5907
(2018/05/14)
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- Palladium-Catalyzed Cross-Coupling of Silyl Electrophiles with Alkylzinc Halides: A Silyl-Negishi Reaction
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We report the first example of a silyl-Negishi reaction between secondary zinc organometallics and silicon electrophiles. This palladium-catalyzed process provides direct access to alkyl silanes. The delicate balance of steric and electronic parameters of the employed DrewPhos ligand is paramount to suppressing isomerization and promoting efficient and selective cross-coupling.
- Cinderella, Andrew P.,Vulovic, Bojan,Watson, Donald A.
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supporting information
p. 7741 - 7744
(2017/06/21)
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- Investigation of a Late-Stage Derivatization Approach to Isatogens: Discovery of New Reaction Pathways
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We have developed a new strategy for preparing 2-substituted indolone N-oxides (isatogens) by substitution reactions with aryl- and alkyl-organometallic reagents. This approach allows a range of substituents to be incorporated at a late stage and complements existing methods that necessitate their early stage incorporation during substrate preparation. Further chemistry has been found to take place at the nitrone moiety; intramolecular dipolar cycloaddition provides access to angularly fused tricyclic heterocycles. More unusually however, these compounds are prone to further addition by organozinc reagents leading to 2,2-disubstituted 3-oxindole products.
- Edeson, Steven J.,Maduli, Elvis J. M.,Swanson, Stephen,Procopiou, Panayiotis A.,Harrity, Joseph P. A.
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supporting information
p. 83 - 86
(2016/01/26)
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- Radical migration-addition of N-tert-butanesulfinyl imines with organozinc reagents
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A novel migration-addition sequence was discovered for the reaction of enantioenriched N-tert-butanesulfinyl iminoacetate 1a with functionalized benzylzinc bromide reagents, producing tert-leucine derivatives in excellent diastereoselectivity (dr 98:2). The absolute configurations of two new chiral centers were unambiguously assigned by chemical transformations and X-ray crystallography. In addition, the regio- and diastereoselectivities of this novel reaction were both explained through the key N-sulfinamine intermediate M6 generated by the tert-butyl radical attack on the imine. Computational analysis of this reaction process, which was performed at the B3LYP/6-311++G(3df,2p)//B3LYP/6-31G-LANL2DZ level, also supported our proposed two-stage mechanism.
- Huang, Wei,Ye, Jian-Liang,Zheng, Wei,Dong, Han-Qing,Wei, Bang-Guo
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p. 11229 - 11237
(2013/12/04)
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- Stereospecific preparation of polyfunctional olefins by the carbometalation of alkynes with polyfunctional zinc-copper organometallics. Stereospecific preparation of five-membered carbocycles by intramolecular carbocupration
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The addition of copper reagents prepared by transmetalation from polyfunctional organozinc iodides to reactive alkynes such as 1-(methylthio)-1-hexyne, phenylacetylene and acetylene, leads to stereochemically well-defined (syn addition), highly functionalized alkenylcopper reagents that after protonation, allylation, iodolysis, or stannylation afford stereochemically pure di-, tri-, and tetrasubstituted olefins. A similar intramolecular carbocupration has allowed the preparation of highly substituted five-membered carbocycles. Compared to lithium- or magnesium-copper reagents, the highly functionalized copper reagents can contain an ester, nitrile, or chloride function. However, they display a lower reactivity than the lithium- or magnesium-copper reagents and do not react with unactivated terminal alkynes.
- Achyutha Rao,Knochel, Paul
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p. 5735 - 5741
(2007/10/02)
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