Secondary Benzylation Using Benzyl Alcohols Catalyzed by Lanthanoid, Scandium, and Hafnium Triflate
作者:Masahiro Noji、Tomoko Ohno、Koji Fuji、Noriko Futaba、Hiroyuki Tajima、Keitaro Ishii
DOI:10.1021/jo034255h
日期:2003.11.1
alkylation, and trifluoromethanesulfonic acid (triflic acid, TfOH) was also a good catalyst. The catalytic activity of metal triflates and TfOH increased in the order La(OTf)3 < Yb(OTf)3 < TfOH < Sc(OTf)3 < Hf(OTf)4. A mechanistic study was also performed. The reaction of 1-phenylethanol (4a) in the presence of Sc(OTf)3 in nitromethane gave an equilibrium mixture of 4a and bis(1-phenylethyl) ether (54). Addition
仲苄醇和三氟甲磺酸金属盐(例如La,Yb,Sc和Hf三氟甲磺酸盐)在硝基甲烷中的结合是一种高效的仲苄基化系统。碳(芳族化合物,烯烃,乙酸烯醇酯),氮(酰胺衍生物)和氧(醇)亲核试剂的二级苄基化反应是在水中存在的情况下,用仲苄醇和0.01-1 mol%的三氟甲磺酸金属盐进行的。带有酸敏感官能团的仲苄醇和亲核试剂(例如,叔丁基二甲基甲硅烷氧基和乙酰氧基以及甲基和苄基酯)可用于烷基化。Hf(OTf)4是该烷基化反应最活跃的催化剂,三氟甲磺酸(三氟甲磺酸,TfOH)也是一种很好的催化剂。金属三氟甲磺酸酯和TfOH的催化活性按La(OTf)3 < Yb(OTf)3