Ytterbium Trifluoromethanesulfonate Yb(OTf)3: An Efficient, Reusable Catalyst for Highly Selective Formation of β-Alkoxy Alcohols via Ring-Opening of 1,2-Epoxides with Alcohols
作者:Pravin R. Likhar、Manyam Praveen Kumar、Ananda K. Bandyopadhyay
DOI:10.1055/s-2001-14909
日期:——
Ytterbium(III)triflate-catalysed ring-opening reactions of epoxides derived from styrene, cyclohexene, norbornene and stilbene, in the presence of alcohols (C1-C4 1°, 2° and 3° aliphatic alcohols, cyclohexyl alcohol, allyl and propargyl alcohol) resulted in the formation of β-alkoxy alcohols in good to excellent yield with high regio-, and where applicable, stereoselectivity. Reaction of stilbene oxide with methanol in the presence of the diethyl ester of l-(+)-tartaric acid afforded the threo form of 1,2-diphenyl-2-methoxy ethanol with high diastereoselectivity (de 94%). Mechanistic implications of the results are discussed.
在醇类(C1-C4 1°、2°和 3°脂肪族醇、环己醇、烯丙基醇和丙炔醇)存在下,镱(III)催化环氧化物的开环反应,从苯乙烯、环己烯、降冰片烯和二苯乙烯衍生出的环氧化物形成δ-烷氧基醇,收率良好至极佳,具有高区域选择性和适当的立体选择性。在存在 l-(+)- 酒石酸二乙酯的情况下,氧化二苯乙烯与甲醇反应,可以得到 1,2-二苯基-2-甲氧基乙醇的苏式形式,具有很高的非对映选择性(de 94%)。讨论了这些结果的机理意义。