Langer P, Döring M, Seyferth D, Görls H
Institut für Organische Chemie der Georg-August-Universität Göttingen, Germany.
Chemistry. 2001 Feb 2;7(3):573-84. doi: 10.1002/1521-3765(20010202)7:3<573::aid-chem573>3.0.co;2-i.
The first elimination reactions of silyl enol ethers to lithiated allenes are reported. These reactions allow a direct transformation of readily available silyl enol ethers into functionalized allenes. The action of three to four equivalents of lithium diisopropylamide (LDA) on silyl enol ethers results in the formation of lithiated allenes by initial allylic lithiation, subsequent elimination of a lithium silanolate, and finally, lithiation of the allene thus formed. Starting with amide-derived silyl imino ethers, lithiated ketenimines are obtained. A variety of reactions of the lithiated allenes with electrophiles (chlorosilanes, trimethylchlorostannane, dimethyl sulfate and ethanol) were carried out. Elimination of silanolate is observed only for substrates that contain the hindered SiMe2tBu or Si(iPr)3 moiety, but not for the SiMe3 group. The reaction of 1,1-dilithio-3,3-diphenylallene with ketones provides a convenient access to novel 1,1-di(hydroxymethyl)allenes which undergo a domino Nazarov-Friedel-Crafts reaction upon treatment with p-toluenesulfonic acid.
首次报道了硅烯醇醚与锂化丙二烯的消除反应。这些反应可将易于获得的硅烯醇醚直接转化为官能化丙二烯。三到四当量的二异丙基氨基锂（LDA）作用于硅烯醇醚，通过初始烯丙基锂化、随后消除硅醇锂盐，最终使由此形成的丙二烯锂化，从而生成锂化丙二烯。从酰胺衍生的硅基亚氨基醚开始，可得到锂化烯酮亚胺。进行了锂化丙二烯与亲电试剂（氯硅烷、三甲基氯锡烷、硫酸二甲酯和乙醇）的各种反应。仅对于含有受阻的SiMe2tBu或Si(iPr)3部分的底物观察到硅醇盐的消除，而对于SiMe3基团则未观察到。1,1-二锂化-3,3-二苯基丙二烯与酮的反应为制备新型1,1-二（羟甲基）丙二烯提供了一条便捷途径，该化合物在用对甲苯磺酸处理时会发生多米诺Nazarov-傅克反应。
