A thermal O-to-C [1,3]-rearrangement of α-hydroxy acid derived enol ethers was achieved under mild conditions. The 2-aminothiophenol protection of carboxylic acids facilitates formation of the [1,3] precursor and its thermalrearrangement via stabilization of a radical intermediate. Experimental and theoretical evidence for dissociative radical pair formation, its captodative stability via aminothiophenol
Onium amides, generated in situ from the combination of aminosilanes and onium fluorides (R(4)PF, R(4)NF), are employed for the first time as bases for catalytic deprotonative functionalization of C(sp(2))-H and activatedC(sp(3))-H bonds under mild conditions.
Preparation of Functionalized Aryl, Heteroaryl, and Benzylic Potassium Organometallics Using Potassium Diisopropylamide in Continuous Flow
作者:Johannes H. Harenberg、Niels Weidmann、Paul Knochel
DOI:10.1002/anie.202003392
日期:2020.7.20
We report the preparation of lithium‐salt‐free KDA (potassium diisopropylamide; 0.6 m in hexane) complexed with TMEDA (N,N,N′,N′‐tetramethylethylenediamine) and its use for the flow‐metalation of (hetero)arenes between −78 °C and 25 °C with reaction times between 0.2 s and 24 s and a combined flow rate of 10 mL min−1 using a commercial flow setup. The resulting potassium organometallics react instantaneously
我们报告了与TMEDA(N,N,N',N'-四甲基乙二胺)络合的无锂盐KDA(二异丙基钾钾;在己烷中0.6 m)的制备及其在(杂)芳烃之间流金属化的用途-78°C和25°C,反应时间介于0.2 s和24 s之间,使用商业流量设置的总流速为10 mL min -1。生成的有机金属钾与各种亲电子试剂立即反应,例如酮,醛,烷基和烯丙基卤化物,二硫化物,Weinreb酰胺和Me 3SiCl,以高收率提供官能化的(杂)芳烃。该流程成功地扩展到了甲基取代的芳烃和杂芳族化合物的侧向金属化反应,从而形成了各种苄基钾有机金属化合物。无需进一步优化就可以进行金属化放大。
Metal-free deprotonative functionalization of heteroaromatics using organic superbase catalyst
Metal-free deprotonative functionalization of heteroaromatic compounds was achieved using an organic superbase catalyst; an organosilicon additive such as trimethylsilylpropyne was employed for activating the catalytic cycle of 1,2-addition to carbonyl compounds.
Catalytic Deprotonative α-Formylation of Heteroarenes by an Amide Base Generated in Situ from Tetramethylammonium Fluoride and Tris(trimethylsilyl)amine
Heteroarene formylations in DMF solution proceed in the presence of an amidebase catalyst generated in situ from tetramethylammonium fluoride (TMAF) and tris(trimethylsilyl)amine (N(TMS)3). The reaction proceeds at room temperature and has an operationally simple procedure. Various heteroarenes, including benzothiophene, thiophene, benzothiazole, oxazole, and indole derivatives, can be formylated