Benzoheteroles 是药物化学中有价值的支架,但 3-乙烯基 benzoheterole 类似物的直接合成仍未探索。一种合理设计的新型含 1,6-烯炔的炔丙醇已制备用于 3-烯基苯并杂环的模块化合成。实现了 1,6-烯醇与亚磺酸钠的银催化级联自由基磺酰化环化反应,以高收率获得各种 2,3-二取代苯并杂环化合物。此外,1,6-烯醇、芳基重氮盐和 Na 2 S 2 O 5的三组分偶联(作为 SO 2替代品)已经实现以中等到良好的收率提供苯并杂环衍生物。值得注意的是,成功展示了可扩展的反应和后期合成转化。还根据现有实验结果和对照实验提出了一种似是而非的机制。
Organoceriumreagents, prepared from organolithiums and anhydrous cerium (III) chloride, react cleanly with easily enolizable ketones to afford the addition products in good to excellent yields.
A strategy for the synthesis of spiroketal compounds through a tandem iodocyclization of 1-(2-ethynylphenyl)-4-hydroxybut-2-yn-1-one derivatives is presented. This reaction could proceed under very mild conditions in a short time and avoid the use of expensive and toxic metal catalysts. Moreover, the resulting halides can be further exploited by subsequent palladium-catalyzed coupling reactions, which
The first general and regioselective Pd‐catalyzed cyclocarbonylation to give α‐methylene‐β‐lactones is reported. Key to the success for this process is the use of a specific sterically demanding phosphine ligand based on N‐arylated imidazole (L11) in the presence of Pd(MeCN)2Cl2 as pre‐catalyst. A variety of easily available alkynols provide under additive‐free conditions the corresponding α‐methylene‐β‐lactones
Pd(II)-Catalyzed Enantioselective Alkynylation of Unbiased Methylene C(sp<sup>3</sup>)–H Bonds Using 3,3′-Fluorinated-BINOL as a Chiral Ligand
作者:Ye-Qiang Han、Yi Ding、Tao Zhou、Sheng-Yi Yan、Hong Song、Bing-Feng Shi
DOI:10.1021/jacs.9b01124
日期:2019.3.20
Pd(II)-catalyzed enantioselective alkynylation of unbiased methylene β-C(sp3)-H bonds is reported. The readily accessible and tunable BINOL derivatives are used as chiralligands in C-Hactivation for the first time. 3,3'-Fluorinated-BINOL proved crucial in determining both the reactivity and enantioselectivity. A wide range of carboxylic acid derivatives are well tolerated with high enantioselectivities (up to
Formal Alkylation of Allenes through Highly Selective Radical Cyclizations of Allene-enes
作者:Rong Zeng、Chunling Fu、Shengming Ma
DOI:10.1002/anie.201107747
日期:2012.4.16
example of alkene‐to‐allene radical cyclization of allene‐enes is reported. The highly chemoselective intermolecular radical addition reaction of the alkene and subsequent, exclusive exo‐radical addition to the allene was realized with perfluoroalkyl radicals (see scheme). A subsequent TBAF‐promoted dehydroiodination of the cyclization products forms cyclopentanes and regenerates an allene moiety (TBAF=t