- Palladium-Catalyzed C(sp3)?H Arylation of Primary Amines Using a Catalytic Alkyl Acetal to Form a Transient Directing Group
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C?H Functionalization of amines is a prominent challenge due to the strong complexation of amines to transition metal catalysts, and therefore typically requires derivatization at nitrogen with a directing group. Transient directing groups (TDGs) permit C?H functionalization in a single operation, without needing these additional steps for directing group installation and removal. Here we report a palladium catalyzed γ-C?H arylation of amines using catalytic amounts of alkyl acetals as transient activators (e.g. commercially available (2,2-dimethoxyethoxy)benzene). This simple additive enables arylation of amines with a wide range of aryl iodides. Key structural features of the novel TDG are examined, demonstrating an important role for the masked carbonyl and ether functionalities. Detailed kinetic (RPKA) and mechanistic investigations determine the order in all reagents, and identify cyclopalladation as the turnover limiting step. Finally, the discovery of an unprecedented off-cycle free-amine directed ?-cyclopalladation of the arylation product is reported.
- St John-Campbell, Sahra,Ou, Alex K.,Bull, James A.
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supporting information
p. 17838 - 17843
(2018/11/23)
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- Effect of the Structure of Unsaturated Aliphatic Alcohols on the Hydrogenation Rate over Pd-Ru Membrane Catalyst
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It is shown that the rate of hydrogenation of substituted propargyl and allyl alcohols, as measured in the liquid phase on a membrane Pd-Ru alloy catalyst is described by the two-parameter Taft equation, which accounts for the induction and steric substituent effects.A positive induction effect of the substituent group promotes the reaction, whereas a negative one slows it down; an enhancement in the steric factor decreases the rate of conversion.Both induction and steric effects are stronger in reactions with ethylenic rather than acetylenic alcohols and for trans rather than cis isomers.
- Karavanov, A. N.,Gryaznov, V. M.,Batyrev, I. G.,Olenina, E. G.
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p. 739 - 743
(2007/10/02)
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- Tertiary alkyl-substituted alcohols as perfumes
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The invention relates to the use as perfumes of tertiary, alkyl-substituted alcohols corresponding to the general formula STR1 in which R1 and R2 are individually each a C1-3 alkyl and R3 is a C4-9 alkyl, in compositions containing active chlorine, and to such compositions themselves.
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- BIOMIMETIC METHYL TRANSFER TO OLEFINS
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Conditions have been found under which trisubstituted olefins can be methylated with diaryl methyl sulfonium salts in 2,6-di-t-butylpyridine.The pattern of methylated compounds formed is similar to that of the enzymatic methylation of Δ24 steroids side chains with S-adenosylmethionine as a methyl donor.
- Julia, M.,Marazano, C.
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p. 3717 - 3724
(2007/10/02)
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