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.
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.
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.
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
supporting information, 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.
