15537-53-8Relevant academic research and scientific papers
Catalytic Intermolecular C(sp3)-H Amination: Selective Functionalization of Tertiary C-H Bonds vs Activated Benzylic C-H Bonds
Brunard, Erwan,Boquet, Vincent,Van Elslande, Elsa,Saget, Tanguy,Dauban, Philippe
supporting information, p. 6407 - 6412 (2021/05/29)
A catalytic intermolecular amination of nonactivated tertiary C(sp3)-H bonds (BDE of 96 kcal·mol-1) is reported for substrates displaying an activated benzylic site (BDE of 85 kcal·mol-1). The tertiary C(sp3)-H bond is selectively functionalized to afford α,α,α-Trisubstituted amides in high yields. This unusual site-selectivity results from the synergistic combination of Rh2(S-Tfpttl)4, a rhodium(II) complex with a well-defined catalytic pocket, with tert-butylphenol sulfamate (TBPhsNH2), which leads to a discriminating rhodium-bound nitrene species under mild oxidative conditions. This catalytic system is very robust, and the reaction was performed on a 50 mmol scale with only 0.01 mol % of catalyst. The TBPhs group can be removed under mild conditions to afford the corresponding NH-free amines.
Catalytic, oxidant-free, direct olefination of alcohols using Wittig reagents
Khaskin,Milstein
, p. 9002 - 9005 (2015/05/27)
Reported here is the catalytic, acceptorless coupling of alcohols with in situ generated, non-stabilized phosphonium ylides to form olefins as major products. The reaction uses low catalyst loadings and does not require added oxidants. Hydrogenation of the product is minimized and the reaction leads to Z (aliphatic) or E (benzylic) stereospecificity.
Catalytic reduction of phenyl-conjugated acetylenic halides by nickel(I) salen: Cyclization versus coupling
Mubarak, Mohammad S.,Jennermann, Theodore B.,Ischay, Michael A.,Peters, Dennis G.
, p. 5346 - 5352 (2008/03/14)
Cyclic voltammetry and controlled-potential electrolysis were employed to study the catalytic reduction of five phenyl-conjugated haloalkynes by nickel(I) salen electro-generated at carbon cathodes in dimethylformamide containing tetramethylammonium tetrafluoroborate. Electrocatalytic reduction of 7-bromo- and 7-iodo-1-phenyl-1-heptyne affords the carbocyclic product, benzylidenecyclohexane, in up to 41 % yield, whereas under similar conditions reduction of 5-halo-1-phenyl-1-pentyne and 8-bromo-1-phenyl-1-octyne gives benzylidenecyclobutane and benzylidenecycloheptane, respectively, in very low yield (≤1 %). Dimers, alkynes, and alkenynes are other products formed from the phenyl-conjugated haloalkynes. Dimers (diphenylalkadiynes) derived from 5-halo-1-phenyl-1-pentyne and 8-bromo-1-phenyl-1-octyne are obtained in yields ranging from 85 to 93 %, whereas 1,14-diphenyltetradeca-1,13-diyne (the dimer produced from 7-halo-1-phenyl-1-heptyne) is found in yields of 45-51 %. To account for the formation of the various products, a mechanistic scheme that involves phenyl-conjugated alkynyl radicals arising from nickel(I) salen catalyzed cleavage of the carbon-halogen bond of each substrate was formulated. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Photolysis of 1,1,1-Triarylalkane. A New Photochemical Carbene Generation Process
Shi, Min,Okamoto, Yoshiki,Takamuku, Setsuo
, p. 3821 - 3824 (2007/10/02)
Upon UV irradiation in methanol some 1,1,1-triarylalkanes underwent an α,α-elimination of two aryl groups to give biaryls and the corresponding carbene intermediates, which inserted into the OH bond of the methanol to afford methyl ethers and/or underwent a 1,2-H shift to afford olefins.Furthermore, the efficieny of this elimination was highly dependent upon the bulkiness of the alkyl groups.
Photolysis of 1,1,1-triphenylalkanes
Shi,Okamoto,Takamuku
, p. 6709 - 6712 (2007/10/02)
Photolysis of 1,1,1-triphenylalkane in methanol gave biphenyl, 1-methoxy-1-phenylalkane, and 1-phenylalkene. The generation of the carbene intermediate by photo α,α-elimination of two phenyl groups was presumed.
An Efficient Biogenetic-Type Transformation of 3-Tertiary-hydroxyalkanoic Acids to Olefinic Compounds
Ohta, Shunsaku,Nozaki, Akira,Ohashi, Norihiko,Nishimura, Yuko,Yoneda, Yumiko,Okamoto, Masao
, p. 5144 - 5148 (2007/10/02)
The readily available 3-tertiary-hydroxyalkanoic acids (3) could be smoothly converted to the olefinic compounds (5) by dehydrative decarboxylation, by treatment with N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline.This efficient reaction mimics the olefination at the initial stage of the so-called "mevalonic acid route".Keywords-olefination; biogenetic-type synthesis; β-hydroxyalkanoic acid; mevalonic acid route; dehydrative decarboxylation; β-propiolactone; mixed anhydride; acyl activation; N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline; 1-acyl-1H-imidazole
Synthesis and Addition Reactions of 2-Phenyl-1-cyclopropene-1-carboxylates
Norden, Wolfgang,Sander, Volker,Weyerstahl, Peter
, p. 3097 - 3111 (2007/10/02)
From the olefins 1, 2, and 4 - 7 the 1-chloro-1-cyclopropanecarboxylic acids 15 - 20 are prepareded via the dichlorocyclopropanes 8, 9, and 11 - 14.The trans-isomers 15a - 20a were readily separated.Spiropentane 10 undergoes anionic ring cleavage with BuLi to give finally the ester 33.The tert-butyl esters 21 - 26 yield with KOtBu the cyclopropene esters 27 - 32.The trans-esters 21a - 26a react much faster than the cis-esters b.At C-3 unsubstituted chlorocyclopropane esters, e.g. 34, do not give stable cyclopropene esters even with lithium dialkylamides.Diazomethane adds to the esters 27 - 32 to give the pyrazolines 38 - 43, their isomers a and b being separable.With traces of base the bicyclic pyrazolines are cleaved to 1,4-dihydropyridazines 44 - 46.Cyclopropenes 27 - 30 react with thiophenolate to form the isomeric products 47 - 50; malonate adds to 28 and 31 to give 51, 52.With malononitrile via subsequent reactions the cyclopentadienes 55 - 57 are obtained.
