New Access to 2,3-Disubstituted Quinolines through Cyclization of o-Alkynylisocyanobenzenes
摘要:
[GRAPHICS]o-Alkynylisocyanobenzenes underwent nucleophile-induced intramolecular cyclization to give 2,3-disubstituted quinoline derivatives in high yields. In addition to the oxygen and nitrogen nucleophiles such as methanol and diethylamine, the nucleophilic carbon of the enolate of malonate induced the cyclization effectively. Reaction of 1,4-di(trimethylsilylethynyl)-2,3-diisocyanobenzene with methanol afforded 2,9-dimethoxy-1,10-phenanthroline in good yield.
Palladium-Catalyzed Cascade Process Consisting of Isocyanide Insertion and Benzylic C(sp<sup>3</sup>)–H Activation: Concise Synthesis of Indole Derivatives
作者:Takeshi Nanjo、Chihiro Tsukano、Yoshiji Takemoto
DOI:10.1021/ol302035j
日期:2012.8.17
Synthesis of the indole skeleton was achieved using a Pd-catalyzed cascade process consisting of isocyanide insertion and benzylic C(sp3)–H activation. It was found that slow addition of isocyanide is effective for reducing the amount of catalyst needed and Ad2PnBu is a good ligand for C(sp3)–H activation. The construction of the tetracyclic carbazole skeleton was also achieved by a Pd-catalyzed domino
吲哚骨架的合成是通过Pd催化的级联过程完成的,该过程由异氰酸酯插入和苄基C(sp 3)–H活化组成。研究发现,缓慢添加异氰酸酯可有效减少所需催化剂的量,而Ad 2 P n Bu是C(sp 3)–H活化的良好配体。四环咔唑骨架的构建也通过掺有炔烃插入的Pd催化的多米诺反应来实现。
Sulfinates and thiocyanates triggered 6-<i>endo</i>cyclization of<i>o</i>-alkynylisocyanobenzenes
Diverse 2-sulfonyl- and 2-thiocyanato-3-substituted quinolines were synthesized from o-alkynylisocyanobenzenes by nucleophilic addition of the respective sulfinate sodium salts and ammonium thiocyanate to the isocyanide moiety followed by cyclization. The salient features of the methodology include metal-free, ambient temperature and mild reaction conditions, ease of reagent handling, and broad functional
An efficient synthesis of tetrazolo[1,5‐a]quinolines employing the reaction of o‐alkynylisocyanobenzenes with sodium azide is described. The reaction proceeds through the nucleophilic addition of the azide to the isocyanide and a subsequent by 6‐endo cyclization.
描述了邻炔基异氰基苯与叠氮化钠反应的四唑并[1,5- a ]喹啉的有效合成方法。该反应通过将叠氮化物亲核加成到异氰化物中,然后进行6-内环化来进行。
Photochemical intramolecular cyclization of o-alkynylaryl isocyanides with organic dichalcogenides leading to 2,4-bischalcogenated quinolines
When a mixture of o-alkynylaryl isocyanides and organic dichalcogenides such as diselenides or ditellurides was irradiated with light of wavelength over 300 or 400 nm, the intramolecular cyclization of the isocyanides took place to afford the corresponding 2,4-bischalcogenated quinolines selectively. The photochemical cyclization of 2-(phenylethynyl)phenyl isocyanide could also proceed in the presence of hydrogen transfer reagents such as tris(trimethylsilyl)silane, tributylgermyl hydride, alkanethiols, and benzeneselenol, providing the corresponding 3-phenylquinoline as the result of 2,4-dihydrogenation.
A facile synthesis of various functionalized 3-substituted quinolin-2(1H)-ones through Ag(I) nitrate-catalyzed cyclization of o-alkynylisocyanobenzenes is described. The reaction allows rapid and convenient access to 3-substituted quinolin-2(1H)-one scaffolds in moderate to good yields.