porphyrin-catalyzed allylation of aldehydes with allyltrimethylsilanes is developed. The formation of the aldehyde–cobalt porphyrin complex, the key intermediate for the addition of allylsilanes, is confirmed by theoretical studies and synchrotron-based X-ray absorption fine-structure measurements. Facile dissociation of the product by allylation from the cobalt complex regenerates the active complex with
Monomeric Metal Aqua Complexes in the Interlayer Space of Montmorillonites as Strong Lewis Acid Catalysts for Heterogeneous Carbon-Carbon Bond-Forming Reactions
scandium catalysts (Cu(2+)- and Sc(3+)-monts) were easily prepared by treating Na(+)-mont with the aqueous solution of the copper nitrate and scandium triflate, respectively. The resulting Cu(2+)- and Sc(3+)-monts showed outstanding catalytic activities for a variety of carbon-carbonbond-formingreactions, such as the Michael reaction, the Sakurai-Hosomi allylation, and the Diels-Alder reaction, under
Montmorillonite K10 clay-catalyzed synthesis of homoallylic silyl ethers: an efficient and environmentally friendly Hosomi–Sakurai reaction
作者:Matthew R. Dintzner、Yawo A. Mondjinou、Barrett Unger
DOI:10.1016/j.tetlet.2009.09.051
日期:2009.12
Aromatic aldehydes react with allyltrimethylsilane in the presence of activated Montmorillonite K10 clay to give homoallylic silyl ethers in good to excellent yields.
A mesoporous aluminosilicate (Al-MCM-41) was found to be an effective heterogeneous catalyst for the reaction of both carbonyl compounds and acetals with allylsilanes to afford the corresponding homoallyl silyl ethers and homoallyl alkyl ethers, respectively. Both the mesoporous structure and the presence of aluminum moiety were indispensable for the high catalytic activity of Al-MCM-41. Moreover, Al-MCM-41 could catalyze the reaction of acetals chemoselectively in the presence of the corresponding carbonyl compounds. The solid acid catalyst Al-MCM-41 could be recovered easily by filtration and could be reused three times without a significant loss of catalytic activity. (C) 2011 Elsevier Ltd. All rights reserved.
Davis, Anthony P.; Jaspars, Marcel, Journal of the Chemical Society. Perkin transactions I, 1992, # 16, p. 2111 - 2118