Reduction of Alkynyl α‐Hydroxy Esters: Stereoselective α‐Ketol Rearrangement

Abstract

The α‐ketol rearrangement of tertiary α‐hydroxy esters induced by LiAlH4/acid treatment provides α‐hydroxy ketones in good yields and high diastereoselectivity. A mechanism is proposed for this reaction as well as a model to explain the diastereoselectivity of the rearrangement.

Research Progress of Reactions Participated by α-Hydroxy Ketones

“…图式 8 通过还原炔烃制备 α-仲羟基酮类化合物 Scheme 8 Synthesis of α-secondary hydroxyketones through reduction of alkynes 1.2.3 通过 α-羟基酯的重排反应制备 α-仲羟基酮类化 合物 2010 年, Cossy 课题组 [18] 报道了 α-叔羟基酯 18 首 先被 LiAlH 4 还原为醛, 然后在酸性条件下发生酮重排 反应, 生成 α-羟基酮衍生物 19, 该方法产率高, 非对映 选择性优异(Scheme 9).…”

Gold-Catalyzed [2,3]-Sigmatropic Rearrangement: Reaction of Aryl Allyl Alcohols with Diazo Compounds

“…With the optimal conditions established, we studied substrate scope by reacting cinnamyl alcohol with a variety of α-aryl-α-diazoacetates (Scheme ). As expected, diazo esters comprising ethyl, methyl, and isopropyl groups had no significant effect on the outcome of the reaction and gave 3aa , 3ab , and 3ac in 72, 91, and 71%, respectively (Scheme ). However, varying substituents on the aromatic group of the diazo compound resulted in a considerable change in the yield of the desired products.…”