21963-38-2Relevant academic research and scientific papers
Dichotomous Reaction Pathways for the Oxidative Palladium(II)-Catalyzed Intramolecular Acyloxylation of Alkenes
Louafi, Fadila,Lorion, Mélanie M.,Oble, Julie,Poli, Giovanni
, p. 2237 - 2242 (2015)
This work provides an in-depth investigation of the Pd(II)-catalyzed oxidative cyclization of various alkenoic acids bearing different tethers between the carboxylic acid moiety and the olefin function, showcasing how different mechanistic pathways (oxypalladation or allylic C-H activation) can be operative. The factors biasing toward one or the other of these reactivities are rationally discussed and compared with our recent studies on the Pd(II)-catalyzed intramolecular amination.
Regiochemistry of Palladium(II)assisted oxidative lactonisation reactions
Annby, Ulf,Stenkula, Magnus,Andersson, Carl-Magnus
, p. 8545 - 8548 (1993)
The Pd(II)-assisted lactonisation of alkenoic acids has been studied. The selectivity, persisting to formation of 5- and 6-membered unsaturated lactones, can be governed by the change of solvent and/or base.
A practical system for manganese(III)-mediated electrochemical synthesis of sorbic acid precursors
Coleman,Hallcher,HcMackins,Rogers,Wagenknecht
, p. 809 - 829 (1991)
An efficient, practical, electrochemical system was developed for the synthesis of a mixture of 4-acetoxy-5-hexenoic acid and trans-6-acetoxy-4-hexenoic acid via manganese (III)-mediated oxidation of acetic acid-acetic anhydride in the presence of butadiene. Copper (II) co-catalyst enhanced the efficiency of this oxidation and copper (I) was shown to catalyze in situ conversion of the acetoxyhexenoic acids into γ-vinyl-γ- butyrolactone.
Synthesis of Unsaturated Lactones via Palladium-Catalyzed Cyclization of Alkenoic Acids
Larock, Richard C.,Hightower, Timothy R.
, p. 5298 - 5300 (1993)
Acyclic and cyclic, aliphatic or aromatic, 4- or 5-alkenoic acids cyclize in high yield to 5- or 6-membered unsaturated lactones using 5 mol percent Pd(OAc)2, 2 equiv of NaOAc, and 1 atm O2.
A Facile Method for the Preparation of γ-Alkenyl-γ-butyrolactones
Kawashima, Masatoshi,Fujisawa, Tamotsu
, p. 3377 - 3379 (1988)
Methyl substituted γ-alkenyl-γ-butyrolactones were prepared from easily available α,β-unsaturated aldehydes such as acrylaldehyde, methacrylaldehyde, crotonaldehyde, and 3-methyl-2-butenal.
Migratory Hydrogenation of Terminal Alkynes by Base/Cobalt Relay Catalysis
Liu, Bingxue,Liu, Qiang,Liu, Xufang
, p. 6750 - 6755 (2020/03/13)
Migratory functionalization of alkenes has emerged as a powerful strategy to achieve functionalization at a distal position to the original reactive site on a hydrocarbon chain. However, an analogous protocol for alkyne substrates is yet to be developed. Herein, a base and cobalt relay catalytic process for the selective synthesis of (Z)-2-alkenes and conjugated E alkenes by migratory hydrogenation of terminal alkynes is disclosed. Mechanistic studies support a relay catalytic process involving a sequential base-catalyzed isomerization of terminal alkynes and cobalt-catalyzed hydrogenation of either 2-alkynes or conjugated diene intermediates. Notably, this practical non-noble metal catalytic system enables efficient control of the chemo-, regio-, and stereoselectivity of this transformation.
Guiding a divergent reaction by photochemical control: Bichromatic selective access to levulinates and butenolides
Sutar, Revannath L.,Sen, Saumik,Eivgi, Or,Segalovich, Gal,Schapiro, Igor,Reany, Ofer,Lemcoff, N. Gabriel
, p. 1368 - 1374 (2018/02/09)
Allylic and acrylic substrates may be efficiently transformed by a sequential bichromatic photochemical process into derivatives of levulinates or butenolides with high selectivity when phenanthrene is used as a regulator. Thus, UV-A photoinduced cross-metathesis (CM) couples the acrylic and allylic counterparts and subsequent UV-C irradiation initiates E-Z isomerization of the carbon-carbon double bond, followed by one of two competing processes; namely, cyclization by transesterification or a 1,5-H shift and tautomerization. Quantum chemical calculations demonstrate that intermediates are strongly blue-shifted for the cyclization while red-shifted for the 1,5-H shift reaction. Hence, delaying the double bond migration by employing UV-C absorbing phenanthrene, results in a selective novel divergent all-photochemical pathway for the synthesis of fundamental structural motifs of ubiquitous natural products.
Catalytic Dehydrative Lactonization of Allylic Alcohols
Liu, Ji,Miotto, Romain J.,Segard, Julien,Erb, Ashley M.,Aponick, Aaron
supporting information, p. 3034 - 3038 (2018/05/28)
A convenient strategy for the synthesis of phthalides and ?-butyrolactones is reported. The method utilizes readily prepared allylic alcohols in formal Au(I)- and Pd(II)-catalyzed SN2′ reactions. Using these catalysts, exclusive formation of the desired five-membered lactones is observed, completely avoiding the competing direct lactonization pathway that forms the undesired seven-membered ring with protic acids and alternative metal salts. This mild and operationally simple method notably tolerates exomethylene groups and should find use in both phthalide and terpene syntheses.
An Agostic Iridium Pincer Complex as a Highly Efficient and Selective Catalyst for Monoisomerization of 1-Alkenes to trans-2-Alkenes
Wang, Yulei,Qin, Chuan,Jia, Xiangqing,Leng, Xuebing,Huang, Zheng
, p. 1614 - 1618 (2017/02/05)
A unique Ir complex (tBuNCCP)Ir with the pyridine–phosphine pincer as the sole ligand, featuring a dual agostic interaction between the Ir and two σ C?H bonds from a tBu substituent, has been prepared. This complex exhibits exceptionally high activity and excellent regio- and stereoselectivity for monoisomerization of 1-alkenes to trans-2-alkenes with wide functional-group tolerance. Reactions can be performed in neat reactant on a more than 100 gram scale using 0.005 mol % catalyst loadings with turnover numbers up to 19000.
Synthesis of 2-Ethenylcyclopropyl Aryl Ketones via Intramolecular SN2-like Displacement of an Ester
Jung, Michael E.,Sun, Daniel L.,Dwight, Timothy A.,Yu, Peiyuan,Li, Wei,Houk
supporting information, p. 5138 - 5141 (2016/10/14)
The efficient synthesis of trans-2-ethenylcyclopropyl aryl ketones via an intramolecular SN2-like displacement of an allylic ester is reported. A novel 1,5-acyl shift process is also observed that contributes to the product mixture. Theoretical calculations provide a rationale for the observed product ratio.
