- Synthesis of diarylmethanes via a Friedel-Crafts benzylation using arenes and benzyl alcohols in the presence of triphenylphosphine ditriflate
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Triphenylphosphine ditriflate (TPPD) was found to be an efficient promoter for the Friedel-Crafts benzylation of arenes with benzyl alcohols in CH 2Cl2 at room temperature. The good yields, the 1:1 molar ratio of arene and benzyl alcohol, the benzylation of chlorobenzene as a nonactivated aromatic compound at room temperature, and no by-product formation are the main advantages of this procedure.
- Khodaei, Mohammad Mehdi,Nazari, Ehsan
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experimental part
p. 5131 - 5135
(2012/09/22)
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- Alkene Hydrofunctionalization Reactions
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A reductive cross coupling reaction process for functionalization of a nucleophilic alkene can be achieved. The nucleophilic alkene and a nucleophilic cross coupling partner compound can be reacted in the presence of an oxidizable alcohol and a suitable catalyst to form a reductive coupling product. Various additives can also be useful to refine the process such as by mitigating certain undesirable intermediates, facilitating specific site selectivity for various substitutions or reaction sites, etc. Chiral additives can be optionally used which act to provide asymmetric catalysis, e.g. allow for regioselective and stereoselective production of reductive coupling products. A reductive cross coupling pathway can include oxidizing the oxidizable alcohol to form a catalyst hydride. The nucleophilic alkene can be inserted into the catalyst hydride to form a catalyst-alkyl intermediate. Further, the catalyst-alkyl intermediate can be transmetallized with the nucleophilic cross coupling partner compound to form a transmetallated intermediate. The catalyst can be reductively eliminated to form the reductive coupling product and a reduced catalyst. Finally, the reduced catalyst can be oxidized under aerobic conditions, for example with oxygen, to form the oxidized catalyst and subsequent repetition through the cyclic pathway.
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Page/Page column 11-13
(2009/04/24)
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- Aerobic alcohol oxidation coupled to palladium-catalyzed alkene hydroarylation with boronic esters
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(Chemical Equation Presented) An oxidation exercise: An aerobic alcohol oxidation coupled with a regioselective palladium-catalyzed reductive functionalization of styrenes and arylboronic esters has been developed (see scheme). The mechanism is thought to proceed by initial oxidation of the solvent to generate a PdII-hydride species, which subsequently reacts with the alkene and arylboronic ester to ultimately generate a new C-C bond.
- Iwai, Yasumasa,Gligorich, Keith M.,Sigman, Matthew S.
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p. 3219 - 3222
(2008/12/23)
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