Formation of CCbonds from CO2 is a much sought after reaction in organic synthesis. To date, other than CH carboxylations using stoichiometric amounts of metals, base, or organometallic reagents, little is known about CC bond formation. In fact, to the best of our knowledge no catalyticmethylation of CHbondsusing CO2 and H2 has been reported. Described herein is the combination of CO2 and H2 for efficient
由CO 2形成CC键是有机合成中非常需要的反应。迄今为止,除了使用化学计算量的金属,碱或有机金属试剂进行的CH羧化反应外,对CC键的形成知之甚少。实际上,据我们所知,没有报道使用CO 2和H 2催化CH键的甲基化。本文描述的是CO 2和H 2的组合,用于碳亲核试剂(如吲哚,吡咯和富电子芳烃)的有效甲基化。使用低聚甲醛的对比实验显示出与CO 2相似的反应性/ H 2系统。
New indole synthesis starting with o-methylphenyl isocyanides such as o-tolyl, 2,4-xylyl, and 2,6-xylyl isocyanide is described in full detail. Treatment of o-tolylisocyanide with LDA in diglyme at −78 °C generated selectively o-(lithiomethyl)phenyl isocyanide in an almost quantitative yield, which on warming up to room temperature was cyclized to indole after aqueous workup. Similary, 2,4-xylyl and
A nickel-catalyzed heteroannulation has been developed where o-haloanilines react with alkynes to afford 2,3-disubstituted indoles. IPr (1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) was found to be an effective ligand for the reaction.
Palladium-catalyzed annulation of internal alkynes in aqueous medium
作者:Wei Jie Ang、Chih-Hsuan Tai、Lee-Chiang Lo、Yulin Lam
DOI:10.1039/c3ra46010j
日期:——
To facilitate precatalyst recovery and reuse, we have developed a fluorous, oxime-based palladacycle 1 and demonstrated that it is a very efficient and versatile precatalyst for carbo- and heteroannulation of internal alkynes with functionalized aryl halides in aqueous medium. A uniform reaction condition for these annulation reactions was also developed.
Traceless solid phase synthesis of 2,3-disubstituted indoles
作者:Adrian L. Smith、Graeme I. Stevenson、Christopher J. Swain、JoséL. Castro
DOI:10.1016/s0040-4039(98)01824-3
日期:1998.11
An efficient method for the traceless solid phase synthesis of 2,3-disubstitutedindoles using a THP linker and a Pd(0)-mediated annulation of 2-iodoaniline and acetylenes is reported.