The Heck reaction of aryl iodides and bromides with allyl ethers has been investigated. Using phosphinefree Pd(OAc)(2) in DNIF at 90 degrees C in the presence of Bu4NOAc, the reaction gave cinnamyl derivatives, usually in good to high yields, with a wide range of aryl halides. The reaction tolerates a variety of functional groups, including ether, amide, alcohol, aldehyde, ketone, ester, cyano, carboxylic acid, and nitro groups. Ortho-substituted arylating agents afforded moderate yields in some cases, though good to high yields were obtained with o-iodotoluene, iodovanillin, and 1-iodonaphthalene. Several pieces of experimental evidence suggest that the observed selectivity in formation of the vinylic substitution products is kinetic in origin under these conditions. A DFT investigation has been performed to clarify the source of product selectivity and, in particular, the preference for cinnamyl ether over enol ether products. Interestingly, it was found that the product selectivity does not arise from competing beta-hydride eliminations but rather from a competition between beta-elimination and hindered single-bond rotation in the initial carbopalladation product.

Unusual selectivity-determining factors in the phosphine-free Heck arylation of allyl ethers / Ilaria, Ambrogio; Fabrizi, Giancarlo; Cacchi, Sandro; Signe Teuber, Henriksen; Peter, Fristrup; David, Tanner; Per Ola, Norrby. - In: ORGANOMETALLICS. - ISSN 0276-7333. - 27:13(2008), pp. 3187-3195. [10.1021/om800114a]

Unusual selectivity-determining factors in the phosphine-free Heck arylation of allyl ethers

FABRIZI, Giancarlo;CACCHI, Sandro;
2008

Abstract

The Heck reaction of aryl iodides and bromides with allyl ethers has been investigated. Using phosphinefree Pd(OAc)(2) in DNIF at 90 degrees C in the presence of Bu4NOAc, the reaction gave cinnamyl derivatives, usually in good to high yields, with a wide range of aryl halides. The reaction tolerates a variety of functional groups, including ether, amide, alcohol, aldehyde, ketone, ester, cyano, carboxylic acid, and nitro groups. Ortho-substituted arylating agents afforded moderate yields in some cases, though good to high yields were obtained with o-iodotoluene, iodovanillin, and 1-iodonaphthalene. Several pieces of experimental evidence suggest that the observed selectivity in formation of the vinylic substitution products is kinetic in origin under these conditions. A DFT investigation has been performed to clarify the source of product selectivity and, in particular, the preference for cinnamyl ether over enol ether products. Interestingly, it was found that the product selectivity does not arise from competing beta-hydride eliminations but rather from a competition between beta-elimination and hindered single-bond rotation in the initial carbopalladation product.
2008
01 Pubblicazione su rivista::01a Articolo in rivista
Unusual selectivity-determining factors in the phosphine-free Heck arylation of allyl ethers / Ilaria, Ambrogio; Fabrizi, Giancarlo; Cacchi, Sandro; Signe Teuber, Henriksen; Peter, Fristrup; David, Tanner; Per Ola, Norrby. - In: ORGANOMETALLICS. - ISSN 0276-7333. - 27:13(2008), pp. 3187-3195. [10.1021/om800114a]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/229896
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