Pd-Catalyzed Cross-Coupling Reaction of Sterically Hindered Vinyl Iodides and Organozinc Reagents. Synthesis of Vitamin D Analogues with an Aromatic Ring Attached AT C-17.

ChemInform ◽  
2003 ◽  
Vol 34 (23) ◽  
Author(s):  
Agnieszka Przezdziecka ◽  
Alicja Kurek-Tyrlik ◽  
Jerzy Wicha
Keyword(s):  
Vitamin D ◽  
Aromatic Ring ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Vitamin D Analogues ◽  
Cross Coupling Reaction ◽  
Sterically Hindered ◽  
Organozinc Reagents ◽  
Vinyl Iodides

Pd-Catalyzed Cross-Coupling Reaction of Sterically Hindered Vinyl Iodides and Organozinc Reagents. Synthesis of Vitamin D Analogues with an Aromatic Ring Attached at C-17

2002 ◽  
Vol 67 (11) ◽  
pp. 1658-1668 ◽  
Author(s):  
Agnieszka Przezdziecka ◽  
Alicja Kurek-Tyrlik ◽  
Jerzy Wicha
Keyword(s):  
Vitamin D ◽  
Butyl Ester ◽  
Acid Methyl Ester ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Building Blocks ◽  
Vitamin D Analogues ◽  
Aryl Bromides ◽  
Palladium Catalyzed ◽  
Organozinc Reagents

Palladium-catalyzed coupling of steroid 17-iodo-6β-methoxy-3α,5-cyclo-5α-androst-16-ene (4) 17-iodoandrosta-5,16-dien-3β-ol (5), and structurally similar (3aS,7R,7aR)-benzenesulfonyl-3-iodo-3a-methyl-3a,4,5,6,7,7a-hexahydro-1H-indene (6) with various arylzinc chlorides, which were generated from aryl bromides 8 [1-bromomethylbenzene (8a), O-(triethylsilyl-2-bromophenyl)propan-2-ol (8b), 2-(4-bromophenyl)propan-2-ol (8c), 4-bromobenzonitrile (8d), 4-bromobenzoic acid methyl ester (8e), 4-bromobenzoic acid tert-butyl ester (8f) and 3-bromopyridine (8g)] via aryllihium derivatives (the Negishi coupling) was examined. The respective cross-coupling products were obtained in good yields for all aryl bromides except of 8c and 8e. Building blocks for synthesis of certain vitamin D analogues have been prepared.

scholarly journals Ni-Catalyzed Electrochemical C(sp2)−C(sp3) Cross-Coupling Reactions

2020 ◽  
Author(s):  
Jian Luo ◽  
Bo Hu ◽  
wenda wu ◽  
maowei hu ◽  
Tianbiao Liu
Keyword(s):  
Aryl Halide ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Ambient Conditions ◽  
Acid Modification ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Organozinc Reagents ◽  
Industrial Adoption

Nickel (Ni) catalyzed carbon-carbon (C−C) cross-coupling has been considerably developed in last decades and has demonstrated unique reactivities compared to palladium. However, existing Ni catalyzed cross-coupling reactions, despite success in organic synthesis, are still subject to the use of air-sensitive nucleophiles (i.e. Grignard and organozinc reagents), or catalysts (i.e. Ni<sup>0</sup> pre-catalysts), significantly limiting their academic and industrial adoption. Herein, we report that, through electrochemical voltammetry screening and optimization, the redox neutral C(sp<sup>2</sup>)‒C(sp<sup>3</sup>) cross-coupling can be accomplished in an undivided cell configuration using bench-stable aryl halide or β-bromostyrene (electrophiles) and benzylic trifluoroborate (nucleophiles) reactants, non-precious, bench stable catalysts consisting of NiCl<sub>2</sub>•glyme pre-catalyst and polypyridine ligands under ambient conditions. The broad reaction scope and good yields of the Ni-catalyzed electrochemical coupling reaction were confirmed by 48 examples of aryl/β-styrenyl chloride/bromide and benzylic trifluoroborates. Its potential applications were demonstrated by late-stage functionalization of pharmaceuticals and natural amino acid modification. Furthermore, this electrochemical C−C cross-coupling reaction was demonstrated at gram-scale in a flow-cell electrolyzer for practical industrial adoption. Finally, an array of chemical and electrochemical studies mechanistically indicates that electrochemical C−C cross-coupling reaction proceeds through an unconventional radical trans-metalation mechanism.

scholarly journals Organocopper cross-coupling reaction for C–C bond formation on highly sterically hindered structures

2019 ◽  
Vol 10 (24) ◽  
pp. 6107-6112 ◽  
Author(s):  
Miku Oi ◽  
Ryo Takita ◽  
Junichiro Kanazawa ◽  
Atsuya Muranaka ◽  
Chao Wang ◽  
...  
Keyword(s):  
Bond Formation ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Carbon Bond ◽  
Carbon Carbon Bond ◽  
Cross Coupling Reaction ◽  
Sterically Hindered

A potent cross-coupling methodology that enables efficient carbon–carbon bond formation at sterically hindered sp2- and sp3-carbons has been developed.

scholarly journals Ni-Catalyzed Electrochemical C(sp2)−C(sp3) Cross-Coupling Reactions

2020 ◽  
Author(s):  
Jian Luo ◽  
Bo Hu ◽  
wenda wu ◽  
maowei hu ◽  
Tianbiao Liu
Keyword(s):  
Aryl Halide ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Ambient Conditions ◽  
Acid Modification ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Organozinc Reagents ◽  
Industrial Adoption

Nickel (Ni) catalyzed carbon-carbon (C−C) cross-coupling has been considerably developed in last decades and has demonstrated unique reactivities compared to palladium. However, existing Ni catalyzed cross-coupling reactions, despite success in organic synthesis, are still subject to the use of air-sensitive nucleophiles (i.e. Grignard and organozinc reagents), or catalysts (i.e. Ni<sup>0</sup> pre-catalysts), significantly limiting their academic and industrial adoption. Herein, we report that, through electrochemical voltammetry screening and optimization, the redox neutral C(sp<sup>2</sup>)‒C(sp<sup>3</sup>) cross-coupling can be accomplished in an undivided cell configuration using bench-stable aryl halide or β-bromostyrene (electrophiles) and benzylic trifluoroborate (nucleophiles) reactants, non-precious, bench stable catalysts consisting of NiCl<sub>2</sub>•glyme pre-catalyst and polypyridine ligands under ambient conditions. The broad reaction scope and good yields of the Ni-catalyzed electrochemical coupling reaction were confirmed by 48 examples of aryl/β-styrenyl chloride/bromide and benzylic trifluoroborates. Its potential applications were demonstrated by late-stage functionalization of pharmaceuticals and natural amino acid modification. Furthermore, this electrochemical C−C cross-coupling reaction was demonstrated at gram-scale in a flow-cell electrolyzer for practical industrial adoption. Finally, an array of chemical and electrochemical studies mechanistically indicates that electrochemical C−C cross-coupling reaction proceeds through an unconventional radical trans-metalation mechanism.

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