New Reaction Of Propynol Compouds Catalyzed By Rare Earth Metals

Propargyl alcohol and its derivatives are an important class of organic compounds, such compounds are readily prepared by terminal alkynes reacting with an aldehyde or ketone. Due to the particular structure of these compounds, they can occur Meyer-Schuster rearrangement under Lewis acidic and form a plurality of reaction sites. Therefore, these compounds have attracted extensive research interests. The reactions propynol compounds involved in are mainly divided into three categories:single reactive functional group participation; reactive hydroxyl and alkyne bond the same time participating; the reaction intermediates forming through Meyer-Schuster rearrangement participation. By these reactions, the propargyl alcohol compounds may be applied to the synthesis of many useful organic intermediates.A straightforward and concise method for the highly stereoselective synthesis of a, (3-unsaturated hydrozones by the Y(OTf)3-catalyed cascade propargylic substitution/aza-Meyer-Schuster rearrangement reaction of tertiary propargylic alcohols and para-tolylsulfonohydrazide under an air atmosphere is developed. A series of α,β-unsaturated hydrozones have been synthesized from simple and readily available starting materials in good yields. Furthermore, the obtained α,β-unsaturated hydrozones are converted into pyrazoles under mild reaction conditions.In addition, we have developed method for the highly efficient synthesis of much more reactive functional groups substituted benzene derivatives by the Yb(OTf)3-catalyed the secondary proparglic alcohols and benzoxazole. We have synthesized a series of reactive functional groups substituted benzene derivatives from simple and readily available starting materials in good yields. At the same time, the mechanism of the reaction were studied in detail. According to the experimental results, we propose the possible mechanism of the benzoxazole ring-opening functionalized.