Efficient One-Step Aldol-Type Reaction of Ketones with Acetals and Ketals Mediated by Dibutylboron Triflate/Diisopropylethyl Amine
作者:Lian-Sheng Li、Sanjib Das、Subhash C. Sinha
DOI:10.1021/ol030108u
日期:2004.1.1
one-step Mukaiyama aldol-type reaction has been developed for the synthesis of beta-alkoxy carbonyl compounds starting from ketones and acetals/ketals. The reaction is mediated by a combination of Bu(2)BOTf and i-Pr(2)NEt affording the products in high yields. Formation of the two possible diastereoisomers of the beta-alkoxy ketones from the chiral acetals shows that the condensation takes place by an
In the presence of a catalytic amount of mesoporous aluminosilicate (Al-MCM-41), both allyltrimethylsilane and silyl enol ether reacted with various acetals under mild reaction conditions to afford the corresponding homoallyl ethers and beta-alkoxy ketones, respectively. The catalyst was easily recovered from the reaction mixture and could be reused in the same reaction without a significant loss of catalytic activity. Moreover, Al-MCM-41 exhibited high chemoselectivity for acetal over aldehyde in the reactions. (C) 2010 Elsevier Ltd. All rights reserved.
Selective aldol reactions of acetals on mesoporous silica catalyst
作者:Haruro Ishitani、Masakazu Iwamoto
DOI:10.1016/s0040-4039(02)02563-7
日期:2003.1
Mukaiyama-aldol reactions of carbonyl compounds with silyl enol ethers were well catalyzed on siliceous mesoporous materials (MCM-41). The reactivity of acetals was much higher than that of aldehyde. The reactions proceeded selectively at 273-298 K on the catalyst of 30 mg per mmol of the substrate. (C) 2002 Published by Elsevier Science Ltd.