Sterically Directed Functionalization of Aromatic C−H Bonds: Selective Borylation Ortho to Cyano Groups in Arenes and Heterocycles
作者:Ghayoor A. Chotana、Michael A. Rak、Milton R. Smith
DOI:10.1021/ja0428309
日期:2005.8.1
Ir-catalyzed borylations of 4-substituted benzonitriles are described. In contrast to electrophilic aromatic substitutions and directed ortho metalations, C-H activation/borylation enables functionalization at the 2-position, adjacent to the cyano group, when the 4-subsitutent is larger than cyano. When an excess of borane reagent is used, diborylation can be achieved with a single regioisomer being
描述了 4-取代苄腈的 Ir 催化硼化。与亲电芳香取代和定向邻位金属化相反,当 4-取代基大于氰基时,CH 活化/硼酸化能够在与氰基相邻的 2-位进行官能化。当使用过量的硼烷试剂时,在某些情况下可以通过形成单一区域异构体来实现二硼化。还报道了空间定向硼酸化扩展到氰基取代的五元和六元环杂环。
Harnessing Sulfur(VI) Fluoride Exchange Click Chemistry and Photocatalysis for Deaminative Benzylic Arylation
groups are typically used but result in the generation of stoichiometric amounts of organic waste. Herein, we report an atom-economical activation of benzylic primary amines relying on the sulfur(VI) fluoride exchange (SuFEx) click chemistry and the aza-Ramberg–Bäcklund reaction. This two-step sequence allows the high-yielding generation of 1,2-dialkyldiazenes from primary amines via loss of SO2. Excitation
虽然胺是有机分子中最常见的功能手柄之一,但它是 C-C 键形成的关键,但未被充分利用。为了促进 C-N 键断裂,通常使用大的活化基团,但会导致产生化学计量的有机废物。在此,我们报告了依赖于硫(VI)氟化物交换(SuFEx)点击化学和氮杂-Ramberg-Bäcklund反应的苄基伯胺的原子经济活化。这种两步序列允许通过损失 SO 2从伯胺高产地生成 1,2-二烷基二氮烯。用蓝光和 Ir 光催化剂激发二氮烯,在排出 N 2时提供自由基对,N 2 可以在扩散和被 Ni 催化剂捕获时诱导形成 C(sp 3 )–C(sp 2 ) 键。这种依赖于无痕点击方法的芳基化策略在各种示例中得到了利用,并对其机制进行了研究。