26029-34-5Relevant academic research and scientific papers
Conjugate reduction of α,β-unsaturated carbonyl compounds catalyzed by a copper carbene complex
Jurkauskas, Valdas,Sadighi, Joseph P.,Buchwald, Stephen L.
, p. 2417 - 2420 (2003)
(Matrix presented) An N-heterocyclic carbene copper chloride (NHC-CuCl) complex (2) has been prepared and used to catalyze the conjugate reduction of α,β-unsaturated carbonyl compounds. The combination of catalytic amounts of 2 and NaOt-Bu with poly(methy
2,2′-Biphenol/B(OH)3 catalyst system for Nazarov cyclization
Sugimoto, Kenji,Oshiro, Miyu,Hada, Ryuhei,Matsuya, Yuji
, p. 1019 - 1022 (2019)
A novel catalyst system—a combination of the readily available 2,2′-biphenol with the inexpensive, nontoxic, and eco-friendly B(OH)3—promoted the Nazarov cyclization of activated and inactivated divinyl ketones to afford the corresponding cyclo
Synthesis of Cyclopentenones with Reverse Pauson-Khand Regiocontrol via Ni-Catalyzed C-C Activation of Cyclopropanone
Jang, Yujin,Lindsay, Vincent N. G.
supporting information, p. 8872 - 8876 (2020/12/02)
A formal [3 + 2] cycloaddition between cyclopropanone and alkynes via Ni-catalyzed C-C bond activation has been developed, where 1-sulfonylcyclopropanols are employed as key precursors of cyclopropanone in the presence of trimethylaluminum. The transformation provides access to 2,3-disubstituted cyclopentenones with complete regiocontrol, favoring reverse Pauson-Khand products, where the large substituent is located at the 3-position of the ring. In the process, the trimethylaluminum additive is thought to play multiple roles, including as a Br?nsted base triggering the equilibration to cyclopropanone and liberation of methane, as well as a source of Lewis acid to activate the carbonyl group toward Ni-catalyzed C-C activation.
Unified approach to the sesquiterpenoids, lauranes and cyclolauranes: Total synthesis of (±)-isolaurene
Niyogi,Khatua, Arindam,Bisai, Vishnumaya
supporting information, (2019/07/23)
A general approach to the total synthesis of sesquiterpene, isolaurene (1a) and cyclolaurene (2a) is featured from commercially available 3-methyl cyclopenten-2-one. The strategy includes a Stork-Danheiser sequence concomitant with a Ni(II)-catalyzed conj
Chemo-Enzymatic Oxidative Rearrangement of Tertiary Allylic Alcohols: Synthetic Application and Integration into a Cascade Process
Brenna, Elisabetta,Crotti, Michele,De Pieri, Matteo,Gatti, Francesco G.,Manenti, Gabriele,Monti, Daniela
, p. 3677 - 3686 (2018/06/04)
A chemo-enzymatic catalytic system, comprised of Bobbitt's salt and laccase from Trametes versicolor, allowed the [1,3]-oxidative rearrangement of endocyclic allylic tertiary alcohols into the corresponding enones under an Oxygen atmosphere in aqueous media. The yields were in most cases quantitative, especially for the cyclopent-2-en-1-ol or the cyclohex-2-en-1-ol substrates without an electron withdrawing group (EWG) on the side chain. Transpositions of macrocyclic alkenols or tertiary alcohols bearing an EWG on the side chain were instead carried out in acetonitrile by using an immobilized laccase preparation. Dehydro-Jasmone, dehydro-Hedione, dehydro-Muscone and other fragrance precursors were directly prepared with this procedure, while a synthetic route was developed to easily transform a cyclopentenone derivative into trans-Magnolione and dehydro-Magnolione. The rearrangement of exocyclic allylic alcohols was tested as well, and a dynamic kinetic resolution was observed: α,β-unsaturated ketones with (E)-configuration and a high diastereomeric excess were synthesized. Finally, the 2,2,6,6-tetramethyl-1-piperidinium tetrafluoroborate (TEMPO+BF4?)/laccase catalysed oxidative rearrangement was combined with the ene-reductase/alcohol dehydrogenase cascade process in a one-pot three-step synthesis of cis or trans 3-methylcyclohexan-1-ol, in both cases with a high optical purity. (Figure presented.).
Handy Protocols using Vinyl Nosylates in Suzuki-Miyaura Cross-Coupling Reactions
Dikova, Anna,Cheval, Nicolas P.,Blanc, Aurélien,Weibel, Jean-Marc,Pale, Patrick
supporting information, p. 4093 - 4100 (2016/01/25)
Vinyl nosylates derived from 1,3-dicarbonyl compounds could be engaged in Suzuki-Myaura cross coupling reactions with aryl-, vinyl- and methylboronic acids or trifluoborate derivatives at room temperature in the presence of 2mol% of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) [PdCl2(dppf)]. One-pot procedures have been set up for practical and efficient nosylation-cross-coupling reactions. Nosylate, as a cheap novel pseudo-halide, gives very stable compounds and is very efficient in Suzuki-Myaura cross coupling reactions (21 examples, 44-99%).
Rh-catalyzed reagent-free ring expansion of cyclobutenones and benzocyclobutenones
Chen, Peng-Hao,Sieber, Joshua,Senanayake, Chris H.,Dong, Guangbin
, p. 5440 - 5445 (2015/09/28)
Here we report a reagent-free rhodium-catalyzed ring-expansion reaction via C-C cleavage of cyclobutenones. A variety of poly-substituted cyclopentenones and 1-indanones can be synthesized from simple cyclobutenones and benzocyclobutenones. The reaction condition is near pH neutral without additional oxidants or reductants. The potential for developing a dynamic kinetic asymmetric transformation of this reaction has also been demonstrated. Further study supports the proposed pathway involving Rh-insertion into the cyclobutenone C-C bond, followed by β-hydrogen elimination, olefin insertion and reductive elimination.
Synthesis of cyclopentenols and cyclopentenones via nickel-catalyzed reductive cycloaddition
Jenkins, Aireal D.,Herath, Ananda,Song, Minsoo,Montgomery, John
supporting information; experimental part, p. 14460 - 14466 (2011/11/04)
Strategies for the reductive cycloaddition of enals or enoates with alkynes have been developed. The enal-alkyne cycloaddition directly affords cyclopentenols, whereas the enoate-alkyne cycloaddition affords the analogous cyclopentenones. The mechanism of
A Pd(II)-catalyzed ring-expansion reaction of cyclic 2-azidoalcohol derivatives: Synthesis of azaheterocycles
Chiba, Shunsuke,Xu, Yan-Jun,Wang, Yi-Feng
supporting information; experimental part, p. 12886 - 12887 (2009/12/06)
(Chemical Equation Presented) A Pd(II)-catalyzed ring expansion-reaction of cyclic 2-azidoalcohol derivatives was found to proceed via an unprecedented C-C bond cleavage-C-N bond formation sequence, providing substituted azaheterocycles.
Cyclopropyl alkynes as mechanistic probes to distinguish between vinyl radical and ionic intermediates
Gottschling, Stephen E.,Grant, Tina N.,Milnes, Kaarina K.,Jennings, Michael C.,Baines, Kim M.
, p. 2686 - 2695 (2007/10/03)
(Chemical Equation Presented) The reactions of (trans-2-phenylcyclopropyl) ethyne, 1a, (trans,trans-2-methoxy-3-phenylcyclopropyl)-ethyne, 1b, and (trans,trans-2-methoxy-1-methyl-3-phenylcyclopropyl)ethyne, 1c, with either aqueous sulfuric acid or tris(trimethylsilyl)silane (or tributyltin hydride) and AIBN have been investigated. Protonation and addition of the silyl (or stannyl) radical occurred at the terminal position of the alkyne giving an α-cyclopropyl-substituted vinyl cation or radical, respectively. Under both reaction conditions, 1a yielded products derived from ring opening toward the phenyl substituent. Alkynes 1b and 1c, however, gave different products depending on whether radical or cationic conditions were used. When radical conditions were employed, products derived from regioselective ring opening toward the phenyl substituent were obtained. In contrast, when cationic conditions were employed, products derived from selective ring opening toward the methoxy substituent were isolated. The corresponding α-cyclopropyl- substituted vinyllithium derivatives were also synthesized and were found to be stable toward rearrangement. An estimate of the rate constants for ring opening of the α-cyclopropylvinyl cations was also made: values of 10 10-1012 s-1 were found for the vinyl cations derived from protonation of the terminal carbon of alkynes 1a-c. Based on these results, cyclopropyl alkynes 1a-c can be classified as hypersensitive mechanistic probes for the detection of vinyl radical or cationic intermediates generated adjacent to the cyclopropyl ring and, in the case of 1b and 1c, the distinction between a radical or cationic intermediate is possible.
