Practical and Scalable Synthesis of Borylated Heterocycles Using Bench-Stable Precursors of Metal-Free Lewis Pair Catalysts
作者:Arumugam Jayaraman、Luis C. Misal Castro、Frédéric-Georges Fontaine
DOI:10.1021/acs.oprd.8b00248
日期:2018.11.16
A practical and scalable metal-free catalytic method for the borylation and borylative dearomatization of heteroarenes has been developed. This synthetic method uses inexpensive and conveniently synthesizable bench-stable precatalysts of the form 1-NHR2-2-BF3-C6H4, commercially and synthetically accessible heteroarenes as substrates, and pinacolborane as the borylation reagent. The preparation of several
已开发出一种实用且可扩展的无杂芳烃的硼化和硼基脱芳香化的无金属催化方法。这种合成方法使用廉价且可方便合成的1-NHR 2 -2-BF 3 -C 6 H 4形式的台式稳定型预催化剂。,市售和合成途径可得到的杂芳烃作为底物,频哪醇硼烷作为硼化试剂。在无溶剂条件下,无需使用Schlenk技术或手套箱即可制备2和50 g规模的数个硼化杂环。使用这种经济高效的绿色方法还可以实现其中一种杂芳烃底物的公斤级硼化,这证明了我们的方法可以在精细化工行业中方便地实施的事实。
Metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane C–H borylation catalysts
作者:Arumugam Jayaraman、Luis C. Misal Castro、Vincent Desrosiers、Frédéric-Georges Fontaine
DOI:10.1039/c8sc01093e
日期:——
1-arylsulfonyl indoles with pinacolborane in a syn addition fashion, with H and Bpin groups added respectively to the 2 and 3 positions of indoles. Catalysis proceeds with good to excellent conversion and essentially with complete regio- and diastereoselectivity. From mechanistic insights and DFT computations, we realized and established that prototypical boranes can also catalyze this borylative dearomatization
尽管通过碳-硼键形成反应使吲哚脱芳香化是新的且很有前途,但到目前为止,它们主要是金属催化的。在这里,我们建立了使用无金属催化剂以原子有效方式促进此类反应的方法。该原位生成的两亲性氨基硼烷催化剂(1-PIP-2-BH 2 -C 6 H ^ 4)2(PIP =哌啶基)促进与频哪醇的各种1-芳基磺酰基吲哚的脱芳构化borylative在一个顺H和BPIn基团分别添加到吲哚的2和3位上。催化进行的转化具有良好至优异的转化率,并且基本上具有完全的区域选择性和非对映选择性。从力学的见解和DFT计算中,我们认识到并确定原型硼烷也可以催化这种硼基脱芳香化反应。
Catalyst-free Synthesis of 6-Hydroxy Indoles via the Condensation of Carboxymethyl Cyclohexadienones and Amines
cyclohexadienones and primary amines has been developed. The aza-Michael addition of the in situ formed enamine, generated through the condensation of carboxymethyl unit of the substrates with an external amine, to cyclohexadienone moiety followed by rearomatization reaction to provide such indoles. Anilines, aliphatic amines, α-chiral aliphatic amines, or even ammonia were used as amine counterpart. Some of
已经开发了由羧甲基环己二酮和伯胺有效地无催化剂合成6-羟基吲哚的方法。通过底物的羧甲基单元与外部胺的缩合产生的原位形成的烯胺的氮杂-迈克尔加成至环己二烯酮部分,然后进行重新芳构化反应以提供这种吲哚。苯胺,脂肪族胺,α-手性脂肪族胺,甚至氨水都用作胺的对应物。使用Re 2 O 7催化剂,一些环己二酮生成6-氨基吲哚而不是6-羟基吲哚。进行了各种方法学后转换,以探索合成的羟基吲哚的合成效用。