Synthesis of Alkoxycarbonyldifluoromethyl-Substituted Semisquarates and Their Transformations

Synthesis ◽  
2018 ◽  
Vol 50 (08) ◽  
pp. 1687-1698 ◽  
Author(s):  
Yoshihiko Yamamoto ◽  
Takashi Kurohara ◽  
Jiang Jiyue ◽  
Masatoshi Shibuya
Keyword(s):  
Carboxylic Acid ◽  
Allylic Alcohol ◽  
Mild Conditions ◽  
Ring Transformations ◽  
Reformatsky Reagent ◽  
Palladium Catalyzed

A novel EtO2CCF2-substituted semisquarate is synthesized from diisopropyl squarate by selective 1,2-addition of the Reformatsky reagent derived from BrCF2CO2Et and subsequent rhenium-catalyzed allylic alcohol rearrangement. The compatibility of the highly reactive EtO2CCF2 group in ring transformations of the obtained semisquarate is investigated. Various EtO2CCF2-substituted, highly functionalized compounds, such as quinones, tetronates, cyclopentenones and a bicyclo-[3.2.0]heptenone, are successfully synthesized by ring transformations of the EtO2CCF2-substituted semisquarate. Also, an allylO2CCF2-substituted semisquarate is prepared and converted into the corresponding tetronate. Subsequent palladium-catalyzed deallylation followed by condensation of the resulting carboxylic acid with several amines under mild conditions affords the corresponding α,α-difluoroamides in good yields.

Stereospecific, Palladium-catalyzed C(sp3)–H Alkenylation and Alkynylation of a Proline Derivative Enabled by 8-Aminoquinoline as a Directing Group

2020 ◽  
Author(s):  
Aleksandra Balliu ◽  
Aaltje Roelofje Femmigje Strijker ◽  
Michael Oschmann ◽  
Monireh Pourghasemi Lati ◽  
Oscar Verho
Keyword(s):  
Carboxylic Acid ◽  
Building Blocks ◽  
Wide Range ◽  
Palladium Catalyzed ◽  
Directing Group ◽  
High Yields ◽  
Vinyl Iodides ◽  
Initial Results

<p>In this preprint, we present our initial results concerning a stereospecific Pd-catalyzed protocol for the C3 alkenylation and alkynylation of a proline derivative carrying the well utilized 8‑aminoquinoline directing group. Efficient C–H alkenylation was achieved with a wide range of vinyl iodides bearing different aliphatic, aromatic and heteroaromatic substituents, to furnish the corresponding C3 alkenylated products in good to high yields. In addition, we were able show that this protocol can also be used to install an alkynyl group into the pyrrolidine scaffold, when a TIPS-protected alkynyl bromide was used as the reaction partner. Furthermore, two different methods for the removal of the 8-aminoquinoline auxiliary are reported, which can enable access to both <i>cis</i>- and <i>trans</i>-configured carboxylic acid building blocks from the C–H alkenylation products.</p>

Aliphatic Carboxylic Acid as Hydrogen-Bond Donor for Converting CO2 and Epoxide into Cyclic Carbonate under Mild Conditions

2021 ◽  
Author(s):  
Zheng Wang ◽  
Yajun Wang ◽  
Qianjie Xie ◽  
Zhiying Fan ◽  
Yehua Shen
Keyword(s):  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Value Added ◽  
Cyclic Carbonate ◽  
Hydrogen Bond Donor ◽  
Title Reaction ◽  
Aliphatic Carboxylic Acid ◽  
Mild Conditions ◽  
Atmospheric Carbon

The coupling of CO2 and epoxide is promising way to reduce atmospheric carbon by converting it into value-added cyclic carbonate. Pursuing efficient catalysts is highly attractive for the title reaction....

scholarly journals General α-Amino 1,3,4-Oxadiazole Synthesis via Late-Stage Reductive Functionalization of Tertiary Amides and Lactams

2021 ◽  
Author(s):  
Daniel Matheau-Raven ◽  
Darren J. Dixon
Keyword(s):  
Carboxylic Acid ◽  
Late Stage ◽  
Coupling Reaction ◽  
Reductive Activation ◽  
Mild Conditions ◽  
Drug Molecules ◽  
Drug Conjugates ◽  
Iminium Ion ◽  
Tertiary Amides ◽  
Coupling Partner

An iridium-catalyzed reductive three-component coupling reaction for the synthesis of medicinally relevant α-amino 1,3,4-oxadiazoles from abundant tertiary amides or lactams, carboxylic acids, and (N-isocyanimino) triphenylphosphorane, is described. Proceeding under mild conditions using (<1 mol%) Vaska’s complex (IrCl(CO)(PPh<sub>3</sub>)<sub>2</sub>) and tetramethyldisiloxane to access the key reactive iminium ion intermediates, a broad range of structurally complex α-amino 1,3,4-oxadiazole architectures were efficiently accessed from diverse carboxylic acid feedstock coupling partners. Extension to α-amino heterodiazole synthesis was readily achieved by exchanging the carboxylic acid coupling partner for C-, S-, or N-centered Brønsted acids, and provided rapid and modular access to these desirable, yet difficult-to-access, heterocycles. Furthermore, the high chemoselectivity of the catalytic reductive activation step allowed the late-stage functionalization of 10 drug molecules, including the synthesis of novel heterodiazole-fused drug-drug conjugates.<br>

scholarly journals Palladium-catalyzed difluoromethylthiolation of heteroaryl bromides, iodides, triflates and aryl iodides

2016 ◽  
Vol 7 (6) ◽  
pp. 3757-3762 ◽  
Author(s):  
Jiang Wu ◽  
Yafei Liu ◽  
Changhui Lu ◽  
Qilong Shen
Keyword(s):  
Mild Conditions ◽  
Aryl Iodides ◽  
Palladium Catalyzed

A palladium-catalyzed difluoromethylthiolation of heteroaryl halides and triflates under mild conditions was described.

Efficient symmetrical bidentate dioxime ligand-accelerated homogeneous palladium-catalyzed Suzuki–Miyaura coupling reactions of aryl chlorides

2017 ◽  
Vol 41 (1) ◽  
pp. 372-376 ◽  
Author(s):  
Jinyi Song ◽  
Hongyan Zhao ◽  
Yang Liu ◽  
Huatao Han ◽  
Zhuofei Li ◽  
...  
Keyword(s):  
High Activity ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Bidentate Ligands ◽  
Aryl Chlorides ◽  
Arylboronic Acids ◽  
Mild Conditions ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed

A series of N,O-bidentate ligands were synthesized and studied as high activity ligands for palladium-catalyzed Suzuki–Miyaura cross-coupling reactions of aryl chlorides with arylboronic acids under mild conditions.

Palladium-Catalyzed Desulfurative Hiyama Coupling of Thioureas to Achieve Amides via Selective C–N Bond Cleavage

Synthesis ◽  
2021 ◽  
Author(s):  
Zhuo Zeng ◽  
Zhanyu He ◽  
Chu Yan ◽  
Mei Zhang ◽  
Majeed Irfan ◽  
...  
Keyword(s):  
Good Yield ◽  
Bond Cleavage ◽  
New Approach ◽  
Mild Conditions ◽  
Palladium Catalyzed

AbstractPalladium-catalyzed Hiyama coupling of active thioureas via selective C–N bond cleavage is reported. Notably, the new approach employed active thioureas as coupling partners in the presence of arylsilanes to give amides in good yield. Further, this strategy, which utilized CuF2 as a key oxidant and activator, afforded various amide products under mild conditions and an easy to handle procedure without extra base.

Palladium-Catalyzed One-Pot Stereospecific Synthesis of 2-Deoxy Aryl C-Glycosides from Glycals and Anilines in the Presence of tert-Butyl Nitrite

Synthesis ◽  
2019 ◽  
Vol 51 (22) ◽  
pp. 4215-4230 ◽  
Author(s):  
Adesh Kumar Singh ◽  
Rapelly Venkatesh ◽  
Jeyakumar Kandasamy
Keyword(s):  
Room Temperature ◽  
Stereospecific Synthesis ◽  
One Pot ◽  
Tert Butyl ◽  
Mild Conditions ◽  
One Pot Synthesis ◽  
Palladium Catalyzed ◽  
Aryl Glycosides

The palladium-catalyzed one-pot synthesis of 2,3-deoxy-3-keto aryl C-glycosides is achieved from glycals and anilines in the presence of tert-butyl nitrite and aqueous HBF4 under mild conditions. This one-pot method stereospecifically provides α- and β-aryl glycosides (≥19:1 by NMR) in good yields at room temperature. The configuration at the C-3 position in the glycal determines the anomeric selectivity (i.e., α or β) of the desired products.

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