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01 Sep 08:47

Steric, Electronic and Conformational Synergistic Effects in the Au(I)-catalyzed alpha-C-H Bond Functionalization of Tertiary Amines

by Fabien, Gagosz
Direct C-H bond functionalization is a useful strategy for the straightforward formation of C-C and C-Heteroatom bonds. In the present work, a unique approach for the challenging electrophilic Au-catalyzed alpha-C-H bond functionalization of tertiary amines is presented. Electronic, steric and conformational synergistic effects exerted by the use of a malonate unit in the substrate were key to the success of this transformation. This new reactivity was applied to the synthesis of tetrahydro-g-carboline products which, under oxidative conditions, could be converted into valuable structural motifs found in bioactive alkaloid natural products
02 Jun 13:50

Synthesis of Sulfonyl Halides from Disulfides or Thiols Using Sodium Hypochlorite Pentahydrate (NaOCl·5H2O) Crystals

by Kirihara, Masayuki

Synthesis
DOI: 10.1055/a-1823-3604



Synthesis of sulfonyl halides using sodium hypochlorite pentahydrate (NaOCl·5H2O) crystals was studied in detail, considering the reaction rate and yield of the desired product. NaOCl·5H2O reacted with disulfides or thiols in acetic acid to produce sulfonyl chlorides. The yields of the desired sulfonyl chlorides were enhanced when the reaction was performed in (trifluoromethyl)benzene under a CO2 atmosphere. The generation of hypochlorous acid (HOCl) was essential for both reactions. Similarly, sulfonyl bromides were prepared via the reaction of disulfides or thiols with sodium bromide and NaOCl·5H2O crystals in acetic acid owing to the generation of hypobromous acid (HOBr). However, the reaction could not proceed in (trifluoromethyl)benzene under a CO2 atmosphere because bromine was produced instead of HOBr.
[...]

Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Article in Thieme eJournals:
Table of contents  |  Abstract  |  Full text

31 May 05:23

Total Synthesis of (−)‐Bastimolide A: A Showcase for Type I Anion Relay Chemistry

by Joshua B. Cox, Alex A. Kellum, Yiwen Zhang, Bo Li, Amos B. Smith
Total Synthesis of (−)-Bastimolide A: A Showcase for Type I Anion Relay Chemistry

The introduction of remote stereochemistry via successive Type I Anion Relay Chemistry (ARC) coupling of commercially available enantioenriched epoxides has enabled a 20-step total synthesis of (−)-bastimolide A. The streamlined assembly and manipulation of ARC products demonstrates a versatile approach that could be leveraged toward other polyhydroxylated macrolides


Abstract

A highly convergent total synthesis of (−)-bastimolide A (1), a polyhydroxy antimalarial macrolide, has been achieved via a longest linear sequence of twenty steps from commercially available glycidyl ethers. Type I Anion Relay Chemistry (ARC) coupling tactics enable rapid construction of the molecule's 1,5-polylol backbone. A late-stage B-alkyl Suzuki–Miyaura union and an Evans-modified Mukaiyama macrolactonization generate the forty-membered Z-α,β-unsaturated macrocyclic lactone.

31 May 05:22

Guest‐Modulated Circularly Polarized Luminescence by Ligand‐to‐Ligand Chirality Transfer in Heteroleptic PdII Coordination Cages

by Kai Wu, Jacopo Tessarolo, Ananya Baksi, Guido H. Clever
Guest-Modulated Circularly Polarized Luminescence by Ligand-to-Ligand Chirality Transfer in Heteroleptic PdII Coordination Cages

Integrative self-assembly of PdII cations with an enantiopure helicene-based ligand and non-chiral but emissive fluorenone ligands yields a series of Pd2L2L′2 heteroleptic coordination cages, showing circularly polarized luminescence (CPL) from the non-chiral moiety. Modulation of the chiroptical properties is achieved by ligand modification or guest binding, achieving an up to 4-fold enhancement of CPL intensity.


Abstract

Multicomponent metallo-supramolecular assembly allows the rational combination of different building blocks. Discrete multifunctional hosts with an accessible cavity can be prepared in a non-statistical fashion. We employ our shape-complementary assembly (SCA) method to achieve for the first time integrative self-sorting of heteroleptic PdII cages showing guest-tunable circularly polarized luminescence (CPL). An enantiopure helicene-based ligand (M or P configuration) is coupled with a non-chiral emissive fluorenone-based ligand (A or B) to form a series of Pd2L2L′2 assemblies. The modular strategy allows to impart the chiral information of the helicenes to the overall supramolecular system, resulting in CPL from the non-chiral component. Guest binding results in a 4-fold increase of CPL intensity. The principle offers potential to generate libraries of multifunctional materials with applications in molecular recognition, enantioselective photo-redox catalysis and information processing.

26 May 08:28

[ASAP] One-Pot Synthesis of 2,3-Disubstituted Indanone Derivatives in Water under Exogenous Ligand-Free and Mild Conditions

by Anqiao Zhu, Yu Sun, Jingru Lai, Ziyan Chen, Xiaoli Bu, Yan-Ni Yue, Mengtao Ma, and Fei Xue

TOC Graphic

The Journal of Organic Chemistry
DOI: 10.1021/acs.joc.2c00544
04 Apr 17:34

Palladium-catalyzed regio- and chemoselective double-alkoxycarbonylation of 1,3-diynes: a computational study

Org. Chem. Front., 2022, 9,2697-2707
DOI: 10.1039/D2QO00122E, Research Article
Jinjin Yang, Deping Kong, Hongli Wu, Zhen Shen, Hongyan Zou, Wentao Zhao, Genping Huang
DFT calculations have been performed to elucidate the detailed reaction mechanism and the origins of the regio- and chemoselectivities of the palladium-catalyzed double-alkoxycarbonylation of 1,3-diynes.
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04 Mar 06:34

Ni‐Catalyzed Cross‐Coupling of 2‐Iodoglycals and 2‐Iodoribals with Grignard Reagents: A Route to 2‐C‐Glycosides and 2’‐C‐Nucleosides

by Janine Cossy, Peter Polák
Ni-Catalyzed Cross-Coupling of 2-Iodoglycals and 2-Iodoribals with Grignard Reagents: A Route to 2-C-Glycosides and 2’-C-Nucleosides

The importance of O/N-glycosides as biologically active compounds cannot be overstated. This study is focused on the functionalization of glycals and ribals at the C2 position with alkyl, vinyl, aryl, heteroaryl and strained ring substituents. The functionalized glycals and ribals were transformed into 2-C-deoxyglycosides and 2’-C-deoxynucleosides. The application to the synthesis of an analogue of cladribine and clofarabine is described.


Abstract

The synthesis of 2-C-glycals and 2-C-ribals was achieved in good yields using a nickel-catalyzed cross-coupling between 2-iodoglycals and 2-iodoribal respectively and Grignard reagents. The prepared 2-C-glycals and ribals were then transformed into 2-C-2-deoxyglycosides, 2-C-diglycosides and 2’-C-2’-deoxynucleosides. The developed method was applied to the synthesis of a 2-chloroadenine

2’-deoxyribonucleoside – a structural analogue of cladribine (Mavenclad®, Leustatin®) and clofarabine (Clolar®, Evoltra®), two compounds used in the treatment of relapsing-remitting multiple sclerosis and hairy cell leukemia.

05 Feb 03:38

[ASAP] Rh(III)-Catalyzed Selective Olefination of N‑Carboxamide Indoles with Unactivated Olefins at Room Temperature via an Internal Oxidation

by Priyambada Prusty, Subramanian Jambu, and Masilamani Jeganmohan

TOC Graphic

Organic Letters
DOI: 10.1021/acs.orglett.1c03905
31 Jan 20:30

Catalytic Addition of Nitroalkanes to Unactivated Alkenes via Directed Carbopalladation

by Keary, Engle
We report a redox-neutral catalytic coupling of nitroalkanes and unactivated alkenes that proceeds by a directed carbopalladation mechanism. The reaction is uniquely enabled by the combination of PdI2 as the precatalyst and HFIP solvent. Structurally complex nitroalkane products, including nitro-containing carbo- and heterocycles, are prepared under operationally convenient conditions without the need for toxic or corrosive reagents. Deuterium labeling experiments and isolation of a catalytically relevant intermediate shed light on the reaction mechanism. By taking advantage of different catalytic activation modes, we demonstrate orthogonal methods for site-selective functionalization of a polyfunctional nitroalkyl ketone.
21 Jan 02:02

[ASAP] Cobalt-Catalyzed C(sp2)C(sp3) SuzukiMiyaura Cross-Coupling Enabled by Well-Defined Precatalysts with L,X-Type Ligands

by L. Reginald Mills, David Gygi, Jacob R. Ludwig, Eric M. Simmons, Steven R. Wisniewski, Junho Kim, and Paul J. Chirik

TOC Graphic

ACS Catalysis
DOI: 10.1021/acscatal.1c05586
05 Jan 18:28

[ASAP] Synthesis of Ester-Substituted Indolo[2,1a]isoquinolines via Photocatalyzed Alkoxycarbonylation/Cyclization Reactions

by Jian-Qiang Chen, Xiaodong Tu, Binyan Qin, Shaoxin Huang, Jun Zhang, and Jie Wu

TOC Graphic

Organic Letters
DOI: 10.1021/acs.orglett.1c04082
21 Nov 11:43

3-Azidoarynes: Generation and Regioselective Reactions

by Jumpei Taguchi
Chemistry Letters, Volume 51, Issue 2, Page 94-98, February 2022.
12 Nov 06:28

Marie Antoinette’s secret messages to Swedish count revealed by chemical analysis

Spectroscopy deciphers censored passages in 200-year-old letters between last French queen and the man rumoured to be her lover