Gold nanoparticles supported on titanium dioxide: an efficient catalyst for highly selective synthesis of benzoxazoles and benzimidazoles
作者:Lin Tang、Xuefeng Guo、Yu Yang、Zhenggen Zha、Zhiyong Wang
DOI:10.1039/c4cc01822b
日期:——
A highly efficient and selective reaction for the synthesis of 2-substitutedbenzoxazoles and benzimidazoles catalyzed by Au/TiO2 has been developed via two hydrogen-transfer processes. This reaction has a good tolerance to air and water, a wide substrate scope, and represents a new avenue for practical C-N and C-O bond formation. More importantly, no additional additives, oxidants and reductants are
aerobic oxidative synthesis of 2-arylbenzo[d]oxazoles, 2-substituted benzo[d]thiazoles, and 1,2-disubstituted benzo[d]imidazoles. N-Heterocyclic carbene (NHC), generated in situ from easily available N-heterocyclic imidazolium salt with air as terminal oxidant, has successfully been utilized as a cheap and efficient catalyst for one-pot aerobic oxidative synthesis of 2-arylbenzo[d]oxazoles, 2-substituted
摘要 N-杂环卡宾(NHC)是由易获得的N-杂环咪唑盐以空气为末端氧化剂原位生成的,已成功地用作便宜且有效的一锅好氧氧化合成2-芳基苯并[ d ]恶唑的催化剂,2-取代的苯并[ d ]噻唑和1,2-二取代的苯并[ d ]咪唑。 N-杂环卡宾(NHC)是由易获得的N-杂环咪唑盐以空气为末端氧化剂原位生成的,已成功地用作便宜且有效的一锅好氧氧化合成2-芳基苯并[ d ]恶唑的催化剂,2-取代的苯并[ d ]噻唑和1,2-二取代的苯并[ d ]咪唑。
Photoinduced Heterogeneous C−H Arylation by a Reusable Hybrid Copper Catalyst
Heterogeneouscopper catalysis enabled photoinducedC−Harylations under exceedingly mild conditions at room temperature. The versatile hybridcoppercatalyst provided step‐economical access to arylated heteroarenes, terpenes and alkaloid natural products with various aryl halides. The hybridcoppercatalyst could be reused without significant loss of catalytic efficacy. Detailed studies in terms of
A new strategy for synthesis of imines using the approach of release of H2 has been developed. This oxidant- and acceptor-free Pd/Ccatalysis protocol is further applied to synthesis of benzoxazoles, benzimidazoles, and benzothiazoles through a one-pot cascade reaction with notably high yields.
benzimidazolium salts, which have an electron deficient imidazolium ring and a carbamate moiety, were allowed to react with superoxide to give ring-opened products and 1-methylbenzimidazoles. The products ratio varied on the change of the counter cation species of superoxide. When 1,1′,3,3′ - tetramethyl- 2,2′-bibenzimidazolium salt reacted with KO2, chemiluminescence was observed which did not occur
使具有缺电子的咪唑环和氨基甲酸酯部分的1-乙氧羰基-3-甲基苯并咪唑鎓盐与超氧化物反应,得到开环产物和1-甲基苯并咪唑。产物比率随超氧化物的反阳离子种类的变化而变化。当1,1',3,3'-四甲基-2,2'-联苯并咪唑鎓盐与KO 2反应时,观察到化学发光,该化学发光未通过使用KOH或H 2 O 2作为试剂而发生。