scholarly journals Oxidative cross-dehydrogenative coupling (CDC) via C(sp2)–H bond functionalization: tert-butyl peroxybenzoate (TBPB)-promoted regioselective direct C-3 acylation/benzoylation of 2H-indazoles with aldehydes/benzyl alcohols/styrenes

RSC Advances ◽  
2021 ◽  
Vol 11 (23) ◽  
pp. 14178-14192
Author(s):  
Richa Sharma ◽  
Lalit Yadav ◽  
Ravi Kant Yadav ◽  
Sandeep Chaudhary
Keyword(s):  
Transition Metal ◽  
Benzyl Alcohols ◽  
Bond Functionalization ◽  
Metal Free ◽  
Tert Butyl ◽  
Dehydrogenative Coupling

An efficient transition-metal-free oxidative C(sp2)–H/C(sp2)–H cross-dehydrogenative coupling via C(sp2)–H bond functionalization for regioselective C-3 acylation/benzoylation of 2H-indazoles with aldehydes/benzyl alcohols/styrenes is reported.

TBHP/n-Bu4PBr-Promoted Oxidative Cross-Dehydrogenative Coupling of Aryl Methanols: A Facile Synthesis of Symmetrical Carboxylic Anhydride Derivatives

Synlett ◽  
2017 ◽  
Vol 29 (01) ◽  
pp. 136-140
Author(s):  
Mehdi Adib ◽  
Rahim Pashazadeh
Keyword(s):  
Transition Metal ◽  
Coupling Reaction ◽  
Catalytic Amount ◽  
Facile Synthesis ◽  
Butyl Hydroperoxide ◽  
Metal Free ◽  
Tert Butyl ◽  
Dehydrogenative Coupling ◽  
Tert Butyl Hydroperoxide ◽  
Methylene Groups

A transition-metal-free oxidative cross-dehydrogenative coupling reaction has been developed for the preparation of symmetrical carboxylic anhydrides through self-coupling dual C–O bond formations of aryl methanols. In the presence of a catalytic amount of tetrabutylphosphonium bromide (TBPB) as transfer agent and aqueous tert-butyl hydroperoxide (TBHP) as oxidant and reactant, methylene groups of aryl methanols were efficiently oxidized to C=O and coupled with the peroxide oxygen from TBHP to form a diverse array of symmetrical carboxylic anhydride derivatives.

scholarly journals Synthesis of 2-oxindoles via 'transition-metal-free' intramolecular dehydrogenative coupling (IDC) of sp2 C–H and sp3 C–H bonds

2016 ◽  
Vol 12 ◽  
pp. 1153-1169 ◽  
Author(s):  
Nivesh Kumar ◽  
Santanu Ghosh ◽  
Subhajit Bhunia ◽  
Alakesh Bisai
Keyword(s):  
Transition Metal ◽  
Alkyl Halides ◽  
One Pot ◽  
Metal Free ◽  
Quaternary Center ◽  
Dehydrogenative Coupling ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds

The synthesis of a variety of 2-oxindoles bearing an all-carbon quaternary center at the pseudo benzylic position has been achieved via a ‘transition-metal-free’ intramolecular dehydrogenative coupling (IDC). The construction of 2-oxindole moieties was carried out through formation of carbon–carbon bonds using KOt-Bu-catalyzed one pot C-alkylation of β-N-arylamido esters with alkyl halides followed by a dehydrogenative coupling. Experimental evidences indicated toward a radical-mediated path for this reaction.

scholarly journals Selective transition-metal-free vicinal cis-dihydroxylation of saturated hydrocarbons

2017 ◽  
Vol 8 (1) ◽  
pp. 452-457 ◽  
Author(s):  
Luis Bering ◽  
Andrey P. Antonchick
Keyword(s):  
Transition Metal ◽  
Reaction Conditions ◽  
Saturated Hydrocarbons ◽  
Bond Functionalization ◽  
Metal Free

A selective vicinal dihydroxylation of alkanes by dual C(sp3)–H bond functionalization under transition-metal-free reaction conditions has been developed.

scholarly journals Transition-metal-free C(sp3)–H/C(sp3)–H dehydrogenative coupling of saturated heterocycles with N-benzyl imines

2020 ◽  
Vol 11 (29) ◽  
pp. 7619-7625 ◽  
Author(s):  
Zhengfen Liu ◽  
Minyan Li ◽  
Guogang Deng ◽  
Wanshi Wei ◽  
Ping Feng ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Transition Metal ◽  
Electron Donors ◽  
Metal Free ◽  
Aryl Radicals ◽  
Dehydrogenative Coupling ◽  
Saturated Heterocycles

A unique transition-metal-free C(sp3)–H/C(sp3)–H dehydrocoupling of N-benzylimines with saturated heterocycles is presented using 2-azaallyl anions as super electron donors to initiate the generation of hydrogen atom abstracting aryl radicals.

(Diacetoxyiodo)benzene-Mediated Transition-Metal-Free Amination of C(sp3)–H Bonds Adjacent to Heteroatoms with Azoles: Synthesis of N-Alkylated Azoles

Synlett ◽  
2018 ◽  
Vol 29 (18) ◽  
pp. 2432-2436 ◽  
Author(s):  
Can Jin ◽  
Weike Su ◽  
Bin Sun ◽  
Zhiyang Yan
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Coupling Reaction ◽  
Metal Catalyst ◽  
Metal Free ◽  
Alternative Method ◽  
Dehydrogenative Coupling ◽  
Wide Range ◽  
Ready Access

A novel PhI(OAc)2-mediated cross-dehydrogenative coupling reaction of α-C(sp3)–H bonds adjacent to a hetero atom with various azoles has been developed, which provides an alternative method for constructing C–N bonds with high atom efficiency. This new protocol requires no metal catalyst and it provides ready access to a wide range of N-alkylated azole derivatives in moderate to excellent yields by using commercially available PhI(OAc)2 as the sole oxidant. Furthermore, the method is effective on a gram scale, which highlights the practicality of this transformation. The result of radical-captured experiments indicated that the transformation might involve a free-radical pathway.

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