- Synthesis of acyclic ketones by catalytic, bidirectional homologation of formaldehyde with nonstabilized diazoalkanes. Application of a chiral diazomethyl(pyrrolidine) in total syntheses of erythroxylon alkaloids
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This work offers a catalytic approach to convergent ketone assembly based upon formal and tandem C-H insertion of diazoalkanes in the presence of limiting amounts of monomeric formaldehyde, which is easily generated as a gas by thermolysis of the inexpensive and abundant paraformaldehyde (~30 USD/kg). The method forms di-, tri-, and even tetrasubstituted acetones with high efficiency, and it has streamlined a synthesis of (-)-dihydrocuscohygrine in which the absolute stereochemistry of a proline-based starting material is preserved. Assisted by the advent of new protocols for hydrazone oxidation, we also provide full details on handling non-carbonyl-stabilized diazo compounds.
- Wommack, Andrew J.,Kingsbury, Jason S.
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p. 10573 - 10587
(2013/11/19)
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- Rhodium-catalyzed acyl-transfer reaction between benzyl ketones and thioesters: Synthesis of unsymmetric ketones by ketone CO-C bond cleavage and intermolecular rearrangement
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In the presence of catalytic amounts of RhH(CO)(PPh3) 3 and 1,2-bis(diphenylphosphino)benzene (dppBz), acyl groups were transferred between benzyl ketones and thioesters/aryl esters. The rhodium complex catalyzed the cleavage of keto
- Arisawa, Mieko,Kuwajima, Manabu,Toriyama, Fumihiko,Li, Guangzhe,Yamaguchi, Masahiko
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supporting information; experimental part
p. 3804 - 3807
(2012/09/07)
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- Metallic Nickel-Mediated Synthesis of Ketones by the Reaction of Benzylic, Allylic, Vinylic, and Pentafluorophenyl Halides with Acid Halides
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Metallic nickel was investigated as a convenient coupling reagent for the synthesis of ketones by the reaction of benzylic, allylic, vinylic, and pentafluorophenyl halides with acid halides at 85 deg C in glyme.A variety of benzylic ketones with functional groups including halogen, cyano, methoxycarbonyl, and hydroxycarbonyl groups were prepared in good yields by this method.The reaction was demonstrated to proceed via organonickel halide intermediates formed by the smooth oxidative addition of benzylic and acyl halides to metallic nickel, which were trapped with electron-deficient olefins. (?-Allyl)nickel halides, prepared in situ at 85 deg C from allylic halides and the nickel, also worked for the preparation of ketones.Vinylic and pentafluorophenyl halides but not alkyl halides reacted with acid halides to give the corresponding ketones in moderate yields.
- Inaba, Shin-ichi,Rieke, Reuben D.
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p. 1373 - 1381
(2007/10/02)
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- Antiprotozoal diamidines
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Diamidines of the formula STR1 wherein X is a propylene, isobutylene, guanidine, pyrrole, tetrazole, imidazole or substituted imidazole group; and 2-[4-(2-imidazolinyl)phenyl]-6-(2-imidazolinyl)indole, are useful in the treatment of certain protozoal infections in mammals, particularly in cattle.
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- ACTIVATED METALLIC NICKEL IN PREPARATION OF SYMMETRICAL 1,3-DIARYLPROPAN-2-ONES FROM BENZYLIC HALIDES AND OXALYL CHLORIDES
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Oxidative addition of benzylic halides to nickel in the metallic state followed by insertion of carbon monoxide generated from alkyl oxalyl chlorides proceeded smoothly to give symmetrical 1,3-diarylpropan-2-ones in moderate yields.
- Inaba, Shin-ichi,Rieke, Reuben D.
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- PHASE TRANSFER CATALYSIS USING COBALT TRICARBONYL NITROSYL
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The first example of the use a mononuclear cobalt complex in a phase-transfer catalyzed process is described.The carbonylation of halides catalyzed by cobalt tricarbonyl nitrosyl gives, depending on the organic substrate, appreciably different results as compared with dicobalt octacarbonyl.
- Gambarotta, Sandro,Alper, Howard
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p. C23 - C26
(2007/10/02)
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