可以通过连续流动进行的分子内逆电子需求杂-/反-Diels-Alder(ih DA / r DA)反应级联,从相应的乙炔基取代的嘧啶中直接获得5-芳基取代的环已吡啶。利用这种新工艺,一系列cycloalka的[ C ^ ]吡啶表示为药物化学有用积木良好制备用短处理时间优异的产率(<45分钟)。重要的是,利用使流体中的溶剂过热的能力允许用甲苯代替通常使用的高沸点溶剂(例如,硝基苯或氯苯)。
Photoredox Cross-Coupling: Ir/Ni Dual Catalysis for the Synthesis of Benzylic Ethers
摘要:
Single-electron transmetalation has emerged as an enabling paradigm for the cross-coupling of C-sp(3) hybridized organotrifluoroborates. Cross-coupling of alpha-alkoxymethyl-trifluoroborates with aryl and heteroaryl bromides has been demonstrated by employing dual catalysis with a combination of an iridium photoredox catalyst and a Ni cross-coupling catalyst. The resulting method enables the alkoxymethylation of diverse (hetero)arenes under mild, room-temperature conditions.
Synthesis of 1,3-dihydrofuro[3,4-]pyridines and 5,7-dihydrofuro[3,4-]pyridines by intramolecular Diels-Alder reactions of pyrimidines. Investigation of the effect of steric interactions on the reaction rate
作者:A.E. Frissen、A.T.M. Marcelis、D.G. Buurman、C.A.M. Pollmann、H.C. van der Plas
DOI:10.1016/s0040-4020(01)89505-3
日期:1989.1
5-propynyloxymethylpyrimidines were synthesized and their intramolecularDiels-Alderreaction was studied. The products of the reaction were 5,7-dihydrofuro[3,4-]pyridines and 1,3-dihydrofuro[3,4-]pyridines, respectively. Introduction of one or two alkyl (aryl) groups at the α or γ position of the side-chain of the 5-propynyloxymethylpyrimidines results in an increased reaction rate. This phenomenon is discussed in terms
Intramolecular cyclization reactions of pyrimidinium cations
作者:A.E. Frissen、G. Geurtsen、A.T.M. Marcelis、H.C. van der Plas
DOI:10.1016/s0040-4020(01)85440-5
日期:1990.1
undergo intramolecularinverseelectrondemandDiels-Alderreactions into the corresponding annelated pyridine derivatives under considerably milder conditions than the corresponding neutral pyrimidines. Protonation of the pyrimidine ring also facilitates the intramolecularDiels-Alderreaction. Protonation of less activated pyrimidines leads, however, to products resulting from an intramolecular coplanar