An efficient one‐pot N‐alkylation of benzimidazole and benzotriazole from carbonyl compounds and tosylhydrazide has been accomplished via copper powder‐catalyzed N—H bond insertion affording N‐alkylated products in good yields. The reaction can tolerate a wide range of carbonyl compounds, such as aryl, alkyl, heterocyclic and α,β‐unsaturated ketones, and aldehydes.
A base‐promoted three‐component coupling of carbon dioxide, amines, and N‐tosylhydrazones has been developed. The reaction is suggested to proceed via a carbocation intermediate and constitutes an efficient and versatile approach for the synthesis of a wide range of organic carbamates. The advantages of this method include the use of readily available substrates, excellent functional group tolerance
Palladium(0)‐catalysed hydro‐alkylation or ‐alkenylation of alkoxyallenes with N‐tosylhydrazones gives direct access to conjugated and skipped 1‐alkoxydienes with high efficiency and excellent functional‐group compatibility. The reaction is proposed to involve the in situ‐formed t‐butanol as proton source in the key step of the allylpalladium(II) species generation. Moreover, lithium iodide or iodobenzene
A novel method for the synthesis of esters via reductive coupling of N‐tosylhydrazones with carboxylicacids under metal‐free conditions has been developed. Various functional groups were found to be tolerable under the reaction conditions to afford low to good yields.
Back to basics: A transition‐metal‐free method developed for the synthesis of indazoles involves an inexpensive catalytic system composed of a diamine and K2CO3. Various (Z)‐2‐bromoacetophenone tosylhydrazones were converted into indazoles at room temperature in excellent yields (see example; Ts=p‐toluenesulfonyl). The yield was improved by photoisomerization with UV light when E/Z isomeric mixtures
简而言之:为合成吲唑而开发的一种无过渡金属的方法涉及由二胺和K 2 CO 3组成的廉价催化体系。各种(Z)-2-溴苯乙酮甲苯磺酰hydr在室温下均以优异的收率转化为吲唑(请参见示例; Ts =对甲苯磺酰基)。当使用原料的E / Z异构体混合物时,通过UV光进行光致异构化提高了产率。