42599-24-6Relevant articles and documents
Asymmetric Synthesis of γ-Lactams Containing α,β-Contiguous Stereocenters via Pd(II)-Catalyzed Cascade Methylene C(sp3)-H Alkenylation/Aza-Wacker Cyclization
Wu, Le-Song,Ding, Yi,Han, Ye-Qiang,Shi, Bing-Feng
, p. 2048 - 2051 (2021)
γ-Lactam containing α,β-contiguous stereogenic centers stands out as a pivotal motif in various bioactive compounds, while its efficient synthesis still needs to be enhanced. Herein, an asymmetric C-H activation strategy for accessing α,β-stereospecific γ-lactams in good yields (≤79%) with high enantio- and diastereoselectivities (≤96% ee and >20:1 dr) was described, which serves as an effective supplement to the existing strategies.
Stereoselective synthesis of (E)- and (Z)-1-alkenyltributylstannanes from (E)- and (Z)-1-alkenyldialkylboranes using a cross-coupling reaction with tributyltin halide
Hoshi, Masayuki,Takahashi, Kou,Arase, Akira
, p. 8049 - 8052 (1997)
The cross-coupling reaction of (E)- or (Z)-1-alkenyldialkylborane with tributyltin halide using copper (II) acetylacetonate [Cu(acac)2] as catalyst in the presence of NaOH proceeds under extremely mild and aqueous conditions to give (E)- or (Z)-1-alkenyltributylstannane stereoselectively.
Stereostructure Clarifying Total Synthesis of the (Polyenoyl)tetramic Acid Militarinone B. A Highly Acid-Labile N-Protecting Group for Amides ?
Drescher, Christian,Brückner, Reinhard
supporting information, p. 6194 - 6199 (2021/08/18)
The 5S, 8′R, and 10′R configurations of militarinone B (3), which is a natural product from Paecilomyces militaris, should equal those in its biosynthetic precursor, militarinone C. The configuration at C-1′ emerged from syntheses of the militarinone B candidates 1′′S- and 1′′R-(5S,8′R,10′R)-3 from the building blocks 9, 11, 14, and 15a while introducing TMB as a more acid-labile N-protecting group for β-ketoamides than DMB. Comparisons of 1′′S- and 1′′R-(5S,8′R,10′R)-3 with natural militarinone B (3; reisolated from Nature) revealed identity versus distinctness.
Intermolecular [2 + 2] Photocycloaddition of α,β-Unsaturated Sulfones: Catalyst-Free Reaction and Catalytic Variants
Jeremias, Noah,Mohr, Lisa-Marie,Bach, Thorsten
supporting information, p. 5674 - 5678 (2021/08/03)
2-Aryl-1-sulfonyl-substituted cyclobutanes were prepared in an intermolecular [2 + 2] photocycloaddition from various α,β-unsaturated sulfones and olefins upon irradiation at λ = 300 nm (26 examples, 60-99% yield). Lewis acids catalyzed the [2 + 2] photocycloaddition of 2-benzimidazolyl styryl sulfones. At short wavelengths, the latter substrates underwent C-S bond cleavage but AlBr3 (5 mol %) allowed for an intermolecular reaction with 2,3-dimethyl-2-butene at longer wavelengths. A chiral-at-metal Lewis acid (2 mol %) facilitated an enantioselective reaction (up to 77% ee).
Copper-Photocatalyzed Hydrosilylation of Alkynes and Alkenes under Continuous Flow
Zhong, Mingbing,Pannecoucke, Xavier,Jubault, Philippe,Poisson, Thomas
, p. 11818 - 11822 (2021/07/10)
Herein, the photocatalytic hydrosilylation of alkynes and alkenes under continuous flow conditions is described. By using 0.2 mol % of the developed [Cu(dmp)(XantphosTEPD)]PF6 under blue LEDs irradiation, a large panel of alkenes and alkynes was hydrosilylated in good to excellent yields with a large functional group tolerance. The mechanism of the reaction was studied, and a plausible scenario was suggested.
Copper-catalyzed cross-coupling of amino acid-derived amides with (Z)-vinyl iodides: Unexpected solvent effect and preparation of plocabulin
Wang, Leiming,Lei, Xinsheng,Wang, Quanrui,Li, Yingxia
, (2021/02/01)
A copper-catalyzed cross-coupling reaction of amino acid-derived amides and (Z)-vinyl iodide was studied to improve a key step in the synthesis of plocabulin, a novel microtubule destabilizer agent of marine origin. The study revealed a profound solvent effect with 1,2-dimethoxyethane (DME), which gave consistently high yields across a large variety of the amide and (Z)-vinyl iodide substrates. The protocol was successfully utilized in the preparation of plocabulin and provided a significantly improved yield.
Oxidative Addition of Alkenyl and Alkynyl Iodides to a AuI Complex
Bower, John F.,Cadge, Jamie A.,Russell, Christopher A.,Sparkes, Hazel A.
supporting information, p. 6617 - 6621 (2020/03/13)
The first isolated examples of intermolecular oxidative addition of alkenyl and alkynyl iodides to AuI are reported. Using a 5,5′-difluoro-2,2′-bipyridyl ligated complex, oxidative addition of geometrically defined alkenyl iodides occurs readily, reversibly and stereospecifically to give alkenyl-AuIII complexes. Conversely, reversible alkynyl iodide oxidative addition generates bimetallic complexes containing both AuIII and AuI centers. Stoichiometric studies show that both new initiation modes can form the basis for the development of C?C bond forming cross-couplings.
Catalyst-free and solvent-free hydroboration of alkynes
Jaladi, Ashok Kumar,Choi, Hyeon Seong,An, Duk Keun
, p. 13626 - 13632 (2020/09/07)
The hydroboration of alkynes with pinacolborane (HBpin) under catalyst- and solvent-free conditions was demonstrated. Various alkynes were smoothly converted into alkenyl boronate esters in good to excellent yields at 110 °C. The gram-scale hydroboration
Rhodium-Catalyzed Deoxygenation and Borylation of Ketones: A Combined Experimental and Theoretical Investigation
Tao, Lei,Guo, Xueying,Li, Jie,Li, Ruoling,Lin, Zhenyang,Zhao, Wanxiang
, p. 18118 - 18127 (2020/11/26)
The rhodium-catalyzed deoxygenation and borylation of ketones with B2pin2 have been developed, leading to efficient formation of alkenes, vinylboronates, and vinyldiboronates. These reactions feature mild reaction conditions, a broad substrate scope, and excellent functional-group compatibility. Mechanistic studies support that the ketones initially undergo a Rh-catalyzed deoxygenation to give alkenes via boron enolate intermediates, and the subsequent Rh-catalyzed dehydrogenative borylation of alkenes leads to the formation of vinylboronates and diboration products, which is also supported by density functional theory calculations.
Stereoselective Synthesis of Vinylboronates by Rh-Catalyzed Borylation of Stereoisomeric Mixtures
Li, Shenhuan,Li, Jie,Xia, Tianlai,Zhao, Wanxiang
, p. 462 - 468 (2019/03/28)
The stereoselective preparation of vinylboronates via rhodium-catalyzed borylation of E/Z mixtures of vinyl actetates is described, and this method was also extended to synthesis of vinyldiboronates. These transformations feature high functional group compatibility and mild reaction conditions. Control experiments support a mechanism that involved a Rh-catalyzed borylation-isomerization sequence. The isomerization of (Z)-vinylboronates to (E)-isomers was also demonstrated.
