Selective Benzylic and Allylic Alkylation of Protic Nucleophiles with Sulfonamides through Double Lewis Acid Catalyzed Cleavage of sp<sup>3</sup>Carbon-Nitrogen Bonds
broad range of tosyl‐activated benzylic and allylic amines to give diversely functionalized products in good to excellent yields and with high regioselectivity. Furthermore, the cross‐coupling reaction of 1,3‐dicarbonyl compounds with benzylic propargylicamine derivatives has been successfully applied to the one‐step synthesis of polysubstituted furans and benzofurans.
A simple and efficient procedure for carbon-carbon bond formation has been developed starting from alcohols and active methylene-containing compounds usingsilica gel supportedsodiumhydrogen sulfate (NaHSO4/SiO2) under mild conditions. NaHSO4/SiO2 can be reused without loss of catalytic activity at least ten times. carbon-carbon coupling - silica gel - alcohol - supported catalysts
Efficient Nucleophilic Substitution of α-Aryl Alcohols with 1,3-Dicarbonyl Compounds Catalyzed by Tin Ion-Exchanged Montmorillonite
作者:Makoto Onaka、Jiacheng Wang、Yoichi Masui
DOI:10.1055/s-0030-1258567
日期:2010.10
Tin ion-exchanged montmorillonite demonstrated the high catalytic activity for the direct nucleophilic substitution of a hydroxyl group in α-aryl alcohols with various 1,3-dicarbonyl compounds including less acidic 1,3-diesters in crude solvents to afford the benzylated products accompanied by water.
The acid mediated reaction between active methylenes and benzhydrylalcohols, or their derivatives, is reported. Ethyl acetoacetate, acetylacetone, and N,N-dibenzyl-malonamic acid methyl ester are benzhydrylated in quantitative yields in the presence of molar amounts of BF 3 .OEt 2 in CH 2 Cl 2 at r.t. TMSOTf and H 2 SO 4 appear to be equally efficient. Use of benzhydryl acetate in place of the starting
报道了活性亚甲基和二苯甲醇或其衍生物之间的酸介导反应。在室温下 CH 2 Cl 2 中存在摩尔量的 BF 3 .OEt 2 时,乙酰乙酸乙酯、乙酰丙酮和 N,N-二苄基-丙二酸甲酯以定量产率二苯甲基化。 TMSOTf 和 H 2 SO 4 似乎是相同的高效的。使用乙酸二苯甲酯代替起始游离醇可以将路易斯酸降低到催化量。介绍了这种几乎没有研究的 CC 键形成的一般机制。由于醇相对于卤化物更容易获得,该方法可以与更经典的基于卤化物的碱性条件进行比较。