Ytterbium triflate and high pressure-mediated ring opening of epoxides with amines

Abstract

Ring opening of epoxides with amines in THF takes place very readily in the presence of catalytic amounts of ytterbium triflate to give the corresponding β-amino alcohols in good to high yields. With tri- and tetra-substituted epoxides, the use of an excess (2–3 equiv.) of the amine is needed. The Yb(OTf)₃-catalysed reaction of epoxides with amines in CH₂Cl₂ is quite complex; the yield of amino alcohols is generally lower and depends upon the addition order of the catalyst, amine and epoxide. The ring opening is accomplished also under high pressures in the absence of Yb(OTf)₃. Ring opening with a combination of Yb(OTf)₃ in CH₂Cl₂ and high pressure is more effective than the use, independently, of either Yb(OTf)₃ or the high-pressure method. Oxetanes and β-lactones undergo ring opening in the presence of Yb(OTf)₃.