We report how an acidic TiCl4-Zn/t-BuOOH system is able to promote the one-pot multicomponent synthesis of beta,beta-disubstituted-beta-aminoalcohols via nucleophilic addition of a hydroxymethyl radical to activated ketimines generated in situ in methanol solvent. While ketimines are generally recognized as less reactive and less stable when compared with aldimines, Ti(IV) plays a key role in facilitating their formation and in enhancing their electrophilic character. As a consequence, the reaction occurs at room temperature and under non-anhydrous conditions in just 1 h, without requiring either the preformation of the ketimine or protection of the amino group. The scope of the reaction is widely explored and a possible mechanism is discussed. (C) 2012 Elsevier Ltd. All rights reserved.
Metallocene catalyzed synthesis of fungistatic vicinal aminoalcohols under solvent free conditions
作者:Gabriela Mancilla、Rosa M. Durán-Patrón、Antonio J. Macías-Sánchez、Isidro G. Collado
DOI:10.1016/j.bmcl.2010.08.109
日期:2010.11
Group 4 and 5 metallocenes, Cp2TiCl2, Cp2ZrCl2 and Cp2VCl2, have been evaluated as catalyst in the solvent free, room temperature, preparation of vicinal aminoalcohols. The regioselectivity of the reaction and the fungistatic activity of the prepared compounds against Botrytis cinerea and Colletotrichum gloeosporioides are discussed. (C) 2010 Elsevier Ltd. All rights reserved.
Multicomponent versus domino reactions: One-pot free-radical synthesis of β-amino-ethers and β-amino-alcohols
aryl amine, a ketone, and a cyclic ether or an alcohol molecule are assembled in a one-pot synthesis by nucleophilic radical addition of ketyl radicals to ketimines generated in situ. The reaction occurs under mild conditions by mediation of the TiCl4/Zn/t-BuOOH system, leading to the formation of quaternary beta-amino-ethers and -alcohols. The new reaction conditions guarantee good selectivity by preventing