129725-59-3

Upstream product

• 64-17-5 ethanol 
• 934-94-1 1-bromo-4-bromoethynyl-benzene 
• 589-87-7 1,4-bromoiodobenzene 
• 2028-63-9 but-3-yn-2-ol 
• 16116-78-2 (4-bromophenyl)(trimethylsilyl)acetylene 
• 81532-79-8 4-(4-bromophenyl)-3-butyn-2-one 

Downstream Products

• 39516-08-0 4-(4-bromophenyl)-2-butanol 
• 81532-79-8 4-(4-bromophenyl)-3-butyn-2-one 
• 1380423-66-4 (E)-benzyl 4-(4-bromophenyl)but-3-en-2-ylcarbamate 
• 26653-39-4 1-(buta-1,2-dien-1-yl)-4-bromobenzene 
• 1201395-05-2 rac-4-(4-bromophenyl)but-3-yn-2-yl mesylate 

Relevant academic research and scientific papers

Aromatic Aza-Claisen Rearrangement of Arylpropargylammonium Salts Generated in situ from Arynes and Tertiary Propargylamines

The charge-accelerated aza-Claisen rearrangement of ammonium salts serves as a key step in the construction of complex nitrogen-containing molecules. However, much less attention has been paid to the aromatic aza-Claisen rearrangement than to the aliphatic one. Herein, we report an unprecedented aromatic aza-Claisen rearrangement of arylpropargylammonium salts, generated in situ from arynes and tertiary propargylamines, delivering structurally diverse 2-propargylanilines in moderate to good yields with high regioselectivity. This rearrangement proceeds in the absence of strong bases or transition metals, is compatible with moisture and air, tolerates a wide variety of functional groups, and is amenable to forming 11- to 13-membered heterocycles with a triple bond. The 2-propargylaniline products were treated with aluminum chloride in ethanol to afford multisubstituted indoles in moderate to excellent yields. Finally, a series of deuterium-labeling experiments was performed to elucidate the reaction mechanism.

Nickel-Catalyzed Asymmetric Friedel-Crafts Propargylation of 3-Substituted Indoles with Propargylic Carbonates Bearing an Internal Alkyne Group

The nickel-catalyzed highly enantioselective Friedel-Crafts propargylation of 3-substituted indoles with propargylic carbonates bearing an internal alkyne group was developed. A wide array of the propargylic carbonates as well as 3-substituted indoles can be applicable to the asymmetric nickel catalysis, providing the corresponding chiral C-3 propargylated indolenine derivatives bearing two vicinal chiral centers in up to 89% yield with up to >99% ee and 94:6 dr (24 examples).

Controllable chemoselectivity in the coupling of bromoalkynes with alcohols under visible-light irradiation without additives: Synthesis of propargyl alcohols and α-ketoesters

The chemoselectivity of visible-light-induced coupling reactions of bromoalkynes with alcohols can be controlled by simple changes to the reaction atmosphere (N2 or O2). A N2 atmosphere favours propargyl alcohols via a direct C-C coupling process, whereas an O2 atmosphere results in the generation of α-ketoesters through the oxidative CC/C-O coupling pathway.

Nickel-Catalyzed Asymmetric Propargylic Amination of Propargylic Carbonates Bearing an Internal Alkyne Group

We have achieved the nickel-catalyzed asymmetric propargylic amination of propargylic carbonates bearing an internal alkyne group. A wide variety of propargylic carbonates and N-methylaniline derivatives were tolerated under the reaction conditions, providing the corresponding chiral propargylic amines in up to 97% yield with up to 97% ee.

Synthesis of Alkylidene(gem-Difluorocyclopropanes) from Propargyl Glycolates by a One-Pot Difluorocyclopropenation/Ireland-Claisen Rearrangement Sequence

A one-pot difluorocyclopropenation/Ireland-Claisen rearrangement sequence applied to readily available propargyl glycolates was developed as a route toward functionalized alkylidene(gem-difluorocyclopropanes). This strategy conveniently avoids the isolation of the unstable 3,3-difluorocyclopropenylcarbinyl glycolates arising from the difluorocyclopropenation. The Ireland-Claisen rearrangement proceeds with high diastereoselectivity and chirality transfer to afford alkylidene(gem-difluorocyclopropanes) incorporating a quaternary stereocenter and a protected glycolic acid moiety, which are useful building blocks for the preparation of functionalized gem-difluorocyclopropanes.

Gold-catalyzed Fluorination of Alkynyl Esters and Ketones: Efficient Access to Fluorinated 1,3-Dicarbonyl Compounds

We developed an efficient synthesis of 2-fluoro-1,3-dicarbonyl compounds using readily available alkynyl ketones or esters as starting material. The key step is the insertion of hydrogen fluoride (HF) to the gold carbene intermediate generated from cationic gold catalyzed addition of N-oxides to alkynyl ketones or esters. This method gives excellent chemical yields and regioselectivity with good functional group tolerance. (Figure presented.).

Gold(I)-catalyzed stereoconvergent, intermolecular enantioselective hydroamination of allenes

Gold and silver: A 1:2 mixture of [{(S)-1}(AuCl)2] and AgBF 4 catalyzes the enantioselective hydroamination of chiral, racemic 1,3-disubstituted allenes with N-unsubstituted carbamates to form N-allylic carbamates in good yield, with high regio- and diastereoselectivity, and up to 92% ee (see scheme, Cbz=benzyloxycarbonyl). Copyright

Highly convenient amine-free sonogashira coupling in air in a polar mixed aqueous medium by trans- and cis-[(NHC)2PdX2] (X = Cl, Br) complexes of N/O-functionalized N-heterocyclic carbenes

Two new trans- and cis[(NHC)2PdX2] (X = Cl, Br) complexes of MO-functionalized N-heterocyclic carbenes employed in a highly convenient amine-free Sonogashira cross-coupling reaction in air in a polar mixed aqueous medium are reported. Specifically, the trans-[{1-benzyl-3-(3,3- dimethyl-2-oxobutyl)imidazol-2-ylidene}2PdBr2] (3) and cw-[{l-benzyl-3-(N-ferf-butylacetamido)imidazol-2-ylid-ene}2PdCl 2] (4) complexes effectively catalyzed the Sonogashira cross-coupling reaction of aryl iodides with substituted acetylenes in air in a mixed solvent (DMF/H2O, 3:1 v/v) under amine-free conditions. Interestingly, these trans- and c/s-[(NHC)2PdX2] (X = Cl, Br) complexes, with two N-heterocyclic carbene ligands, exhibited superior activity compared with the now popular PEPPSI (pyridine enhanced precatalyst preparation, stabilization and initiation)-themed analogues, trans-[(NHC)Pd(pyridine)X2] (X = Cl, Br), 3a and 4a, with one N-heterocyclic carbene ligand and a "throw away" pyridine ligand in a trans disposition to each other. The higher activities of 3 and 4 compared with PEPPSI analogues 3a and 4a are attributed to more-electron-rich metal centers, as revealed by DFT studies, in the former complexes and is in concurrence with a more electron-rich metal center being effective in facilitating the oxidative addition of aryl halide, often a rate-determining step in palladium-mediated cross-coupling reactions. Complexes 3 and 4 were prepared from the corresponding silver analogues by transmetalation with [(COd)PdCl2], whereas the corresponding PEPPSI analogues 3a and 4a were obtained directly from the imidazolium halide salts by reaction with PdCl2 in pyridine in the presence of K2CO3 as base.

Fused pyridine derivatives

The present provides a condensed pyridine compound (I) represented by the following formula: (wherein, R2represents ring A represents benzene ring, pyridine ring, thiophene ring or furan ring; and B represents its pharmaceutically acceptable salt or hydrates thereof, which is a clinically useful medicament having a serotonin antagonism, in particular, that for treating, ameliorating or preventing spastic paralysis or central muscle relaxants for ameliorating myotonia.

Enantioselective synthesis of both enantiomers of various propargylic alcohols by use of two oxidoreductases

The oxidoreductases Lactobacillus brevis alcohol dehydrogenase (LBADH) and Candida parapsilosis carbonyl reductase (CPCR) are suitable catalysts for the reduction of ketones to afford enantiopure sec. alcohols. A broad variety of alkynones (1, 3, and 5) are accepted as substrates and the corresponding propargylic alcohols (2, 4, and 6) are obtained in good yield and excellent enantiomeric excess. By changing the steric demand of the substituents the ee values can be adjusted and even the configurations of the products can be altered.