- Cascade reactions: A new synthesis of 2-benzofuran-2-ylacetamides by sequential Pd(0)-catalyzed deallylation-Pd(II)-catalyzed aminocarbonylative heterocyclization of 1-(2-allyloxyaryl)-2-yn-1-ols
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(Chemical Equation Presented) A general and efficient synthesis of 2-benzofuran-2-ylacetamides 5 starting from 1-(2-allyloxyaryl)-2-yn-l-ols 1, amines 4, and CO, in the presence of catalytic amounts of PdI2 in conjunction with PPh3 and KI, has been developed based on the "sequential homobimetallic catalysis" concept, that is, a process in which two different complexes of the same metal, but in two different oxidation states, promote two catalytic cycles in sequence. The first cycle corresponds to a Pd(0)-catalyzed aminodeallylation of 1 with formation of the free phenol 2, which then undergoes Pd(II)-catalyzed aminocarbonylative heterocyclization to give the final product 5.
- Gabriele, Bartolo,Mancuso, Raffaella,Salerno, Giuseppe,Costa, Mirco
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p. 9278 - 9282
(2008/03/14)
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- 2,4,6-Triphenylpyridine as a Neutral Leaving Group in the Palladium(0)-Catalyzed Allylation of Nucleophiles
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Palladium(0)-catalyzed allylation of nucleophiles such as morpholine, sodium dimethyl malonate and 2,6-dimethylaniline can be achieved under very mild conditions using N-allyl-2,4,6-triphenylpyridinium tetrafluoroborates as allylating reagents in reactions in which 2,4,6-triphenylpyridine acts as the neutral leaving group.
- Moreno-Manas,Morral,Pleixats
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p. 241 - 246
(2007/10/03)
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- Practical palladium-mediated deprotective method of allyloxycarbonyl in aqueous media
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The Allyloxycarbonyl (Alloc) moiety can be removed smoothly and selectively in good yield (73-100%) from allylic esters, carbamates and carbonates by aqueous Pd (O) catalysed allyl transfer to diethylamine in aqueous media employing a water soluble phosphine. The allyl scavenger as well as by product allyl diethylamine are volatile and easily removed in vacuo. In a two phase system an increased selectivity is seen. The method has been successfully used for deprotection of a wide range of secondary amines or base sensitive derivatives and the catalyst is efficiently recycled.
- Genet, Jean Pierre,Blart, Errol,Savignac, Monique,Lemeune, Stephane,Lemaire-Audoire, Sandrine,Paris, Jean-Marc,Bernard, Jean-Marie
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p. 497 - 503
(2007/10/02)
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- PALLADIUM-CATALYZED REACTION OF ALLYL CARBAMATES; ALLYLATION OF CARBONUCLEOPHILES, AND PROTECTION-DEPROTECTION OF AMINES
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Allylation of carbonucleophiles with allylic carbamates under neutral conditions has been studied.The C-allylation of carbonucleophile is competitive with the N-allylation of amines, and the structure of amines is crucial for the selectivity.Bulky secondary amines gave the best results.Also a new method of protection-deprotection of amines as carbamates has been developed.Smooth deprotection is possible by the palladium-catalyzed reaction of allyl carbamates with formic acid.This method is particulary useful for primary amines, including optically active amino acids.
- Minami, Ichiro,Ohashi, Yukihiro,Shimizu, Isao,Tsuji, Jiro
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p. 2449 - 2452
(2007/10/02)
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