36440-63-8Relevant academic research and scientific papers
Visible-light induced metal-free cascade Wittig/hydroalkylation reactions
Miao, Pannan,Li, Ruining,Lin, Xianfeng,Rao, Liangming,Sun, Zhankui
supporting information, p. 1638 - 1641 (2021/03/09)
Cascade reactions are green and powerful transformations for building multiple carbon-carbon bonds in one step. Through a relay olefination and radical addition process, we were able to develop the cascade Wittig/hydroalkylation reactions induced by visible light. This metal-free radical approach features mild conditions, robustness, and excellent functionality compatibility. It allows access to saturated C3 homologation products directly from aldehydes or ketones. The synthetic utility of this method is demonstrated by a two-step synthesis ofindolizidine 209D.
Structure activity relationship exploration of 5-hydroxy-2-(3-phenylpropyl)chromones as a unique 5-HT2B receptor antagonist scaffold
Kim, Minsoo,Truss, Myles,Pagare, Piyusha P.,Essandoh, Martha A.,Zhang, Yan,Williams, Dwight A.
, (2020/09/01)
Antagonists for the serotonin receptor 2B (5-HT2B) have clinical applications towards migraine, anxiety, irritable bowl syndrome, and MDMA abuse; however, few selective 5-HT2B antagonists have been identified. Previous studies from these labs identified a natural product, 5-hydroxy-2-(2-phenylethyl)chromone (5-HPEC, 2) as the first non-nitrogenous ligand for the 5-HT2B receptor. Studies on 5-HPEC optimization led to the identification of 5-hydroxy-2-(3-phenylpropyl)chromone (5-HPPC, 3), which showed a tenfold improvement in binding affinity over 2 at 5-HT2B. This study aimed to further improve receptor pharmacology of this unique scaffold. Guided by molecular modeling studies modifications at the C-3′ and C-4′ positions of 3 were made to probe their effects on ligand binding affinity and efficacy. Among the derivatives synthesized 5-hydroxy-2-(3-(3-cyanophenyl)propyl)chromone (5-HCPC, 3d) showed the most promise with a multifold improvement in binding affinity (pKi = 7.1 ± 0.07) over 3 with retained antagonism.
Radical-Mediated Strategies for the Functionalization of Alkenes with Diazo Compounds
Su, Yong-Liang,Liu, Geng-Xin,Liu, Jun-Wen,Tram, Linh,Qiu, Huang,Doyle, Michael P.
supporting information, p. 13846 - 13855 (2020/09/21)
One of the most common reactions of diazo compounds with alkenes is cyclopropanation, which occurs through metal carbene or free carbene intermediates. Alternative functionalization of alkenes with diazo compounds is limited, and a methodology for the addition of the elements of Z-CHR2 (with Z = H or heteroatom, and CHR2 originates from N2 CR2) across a carbon-carbon double bond has not been reported. Here we report a novel reaction of diazo compounds utilizing a radical-mediated addition strategy to achieve difunctionalization of diverse alkenes. Diazo compounds are transformed to carbon radicals with a photocatalyst or an iron catalyst through PCET processes. The carbon radical selectively adds to diverse alkenes, delivering new carbon radical species, and then forms products through hydroalkylation by thiol-assisted hydrogen atom transfer (HAT), or forms azidoalkylation products through an iron catalytic cycle. These two processes are highly complementary, proceed under mild reaction conditions, and show high functional group tolerance. Furthermore, both transformations are successfully performed on a gram-scale, and diverse γ-amino esters, γ-amino alcohols, and complex spirolactams are easily prepared with commercially available reagents. Mechanistic studies reveal the plausible pathways that link the two processes and explain the unique advantages of each.
Nickel-Catalyzed Cross-Electrophile Coupling of Aryl Chlorides with Primary Alkyl Chlorides
Gilbert, Michael M.,Goldfogel, Matthew J.,Kim, Seoyoung,Weix, Daniel J.
supporting information, p. 9902 - 9907 (2020/06/27)
Alkyl chlorides and aryl chlorides are among the most abundant and stable carbon electrophiles. Although their coupling with carbon nucleophiles is well developed, the cross-electrophile coupling of aryl chlorides with alkyl chlorides has remained a chall
Combined Photoredox/Enzymatic C?H Benzylic Hydroxylations
Betori, Rick C.,May, Catherine M.,Scheidt, Karl A.
, p. 16490 - 16494 (2019/11/03)
Chemical transformations that install heteroatoms into C?H bonds are of significant interest because they streamline the construction of value-added small molecules. Direct C?H oxyfunctionalization, or the one step conversion of a C?H bond to a C?O bond, could be a highly enabling transformation due to the prevalence of the resulting enantioenriched alcohols in pharmaceuticals and natural products,. Here we report a single-flask photoredox/enzymatic process for direct C?H hydroxylation that proceeds with broad reactivity, chemoselectivity and enantioselectivity. This unified strategy advances general photoredox and enzymatic catalysis synergy and enables chemoenzymatic processes for powerful and selective oxidative transformations.
One-Pot Photomediated Giese Reaction/Friedel-Crafts Hydroxyalkylation/Oxidative Aromatization to Access Naphthalene Derivatives from Toluenes and Enones
Liu, Haiwang,Ma, Lishuang,Zhou, Rong,Chen, Xuebo,Fang, Weihai,Wu, Jie
, p. 6224 - 6229 (2018/06/11)
Value-added chemicals, γ-aryl ketones and naphthalenes, were conveniently synthesized from readily available toluenes and enones through the synergistic combination of photoredox and Lewis acid catalysis. The direct synthesis of γ-aryl ketones represents a rare example of Giese reactions between benzylic C(sp3)-H and enones that avoids the use of prefunctionalized metallic nucleophiles. Naphthalene derivatives were accessed through a one-pot Giese reaction/Friedel-Crafts hydroxyalkylation/oxidative aromatization sequential transformation.
α-Diazo-β-ketonitriles: Uniquely reactive substrates for arene and alkene cyclopropanation
Nani, Roger R.,Reisman, Sarah E.
supporting information, p. 7304 - 7311 (2013/06/27)
An investigation of the intramolecular cyclopropanation reactions of α-diazo-β-ketonitriles is reported. These studies reveal that α-diazo-β-ketonitriles exhibit unique reactivity in their ability to undergo arene cyclopropanation reactions; other similar acceptor-acceptor- substituted diazo substrates instead produce mixtures of C-H insertion and dimerization products. α-Diazo-β-ketonitriles also undergo highly efficient intramolecular cyclopropanation of tri- and tetrasubstituted alkenes. In addition, the α-cyano-α-ketocyclopropane products are demonstrated to serve as substrates for SN2, SN2′, and aldehyde cycloaddition reactions.
Ring opening of cyclopropanecarboxylates using samarium(ii) diiodide (SmI2)-HMPA-THF system
Yamashita,Okuyama,Ohhara,Kawasaki,Ohta
, p. 708 - 710 (2007/10/02)
Cyclopropane ring of 2- and 2,3-substituted cyclopropanecarboxylates (1) was regioselectively cleaved using SmI2-HMPA-THF system in the presence of tert-BuOH to give 4- and 3,4-substituted butyrates (2) in moderate to good yields.
Ring opening of cyclopropanemonocarboxylates and 1,1- cyclopropanedicarboxylates using samarium(II) diiodide (SmI2)-HMPA-THF system
Yamashita,Okuyama,Ohhara,Kawasaki,Sakai,Nakata,Kawabe,Kusumoto,Ohta
, p. 2075 - 2081 (2007/10/03)
The cyclopropane ring in 2-substituted 1,1-cyclopropanedicarboxylates was regioselectively opened by using samarium(II) diiodide (Sml2) in a hexamethylphosphoric triamide (HMPA)-tetrahydrofuran (THF) (1:10) system under mild and neutral conditions to give (2-substituted ethyl)malonates in moderate to good yields. The cyclopropane ring in 2-substituted cyclopropanecarboxylates or 2-substituted 3- (trimethylsilyl)cyclopropanecarboxylates was similarly cleaved regioselectively by using Sml2 in a HMPA-THF (1:1) system to give 4- arylbutyrates or 4-aryl-3-(trimethylsilyl)butyrates in 16-89% yields. The reaction mechanism of these ring-opening reactions is discussed.
