An efficient tandem elimination–cyclization–desulfitative arylation of 2-(gem-dibromovinyl)phenols(thiophenols) with sodium arylsulfinates
作者:Wei Chen、Pinhua Li、Tao Miao、Ling-Guo Meng、Lei Wang
DOI:10.1039/c2ob27232f
日期:——
An efficient tandem eliminationâcyclizationâdesulfitative arylation of 2-(gem-dibromovinyl)phenols(thiophenols) with sodium arylsulfinates has been developed. In the presence of TBAFâPdCl2âCu(OAc)2âNEt3, the reactions generated 2-arylbenzofurans(thiophenes) with good yields in one-pot under ligand-free conditions.
The first example of sole direct C–H bond arylation of benzo[b]furans with aryl chlorides was achieved catalyzed by a well-defined NHC-Pd(II)-Im complex. Under the suitable conditions, all reactions involving kinds of benzo[b]furans and (hetero)aryl chlorides proceeded well to give the desired C2-arylated benzo[b]furans in sole regioselectivity in acceptable to high yields, providing an efficient and
明确定义的NHC-Pd(II)-Im络合物催化了苯并[ b ]呋喃与芳基氯的唯一直接C-H键芳基化反应。在合适的条件下,所有涉及各种苯并[ b ]呋喃和(杂)芳基氯化物的反应均能顺利进行,从而以唯一的区域选择性提供所需的C2-芳基化苯并[ b ]呋喃,并以高收率接受,从而提供了有效而经济的途径用于苯并[ b ]呋喃的直接C2-H键芳基化。
Ruthenium NHC Catalyzed Highly Asymmetric Hydrogenation of Benzofurans
H2‐O‐T! Aromatic O‐heterocycles are a challenging substrates for asymmetrichydrogenation (H2). An in situ formed chiral N‐heterocyclic carbene (NHC) ruthenium complex allows the high yielding, completely regioselective, and highlyasymmetrichydrogenation of substituted benzofurans at room Temperature, giving valuable 2,3‐dihydrobenzofurans (see scheme).
H 2 ‐O‐T!芳族O杂环是不对称氢化(H 2)的具有挑战性的底物。原位形成的手性N-杂环卡宾(NHC)钌络合物可在T温度下以高收率,完全区域选择性和高度不对称氢化取代苯并呋喃,得到有价值的2,3-二氢苯并呋喃(参见方案)。
Transition‐Metal‐Free Synthesis of Heterobiaryls through 1,2‐Migration of Boronate Complex
作者:Swagata Paul、Kanak Kanti Das、Samir Manna、Santanu Panda
DOI:10.1002/chem.201904761
日期:2020.2.11
carbon atom. Subsequent oxidation of the intermediate boronic ester afforded heterobiaryls in good yield. A comprehensive 11 B NMR study has been conducted to support the mechanism. The cross coupling between two nucleophilic cross coupling partners without transition metals reveals a reliable manifold to procure heterobiaryls in good yields. Various heterocycles like furan, thiophene, benzofuran, benzothiophene
通过使用锂化的杂环,芳基或杂芳基硼酸酯和亲电卤素源,通过无过渡金属的sp2-sp2交叉偶联策略,可以实现多种杂芳基芳基化合物的合成。杂二芳基的构建是通过亲电活化芳基-杂芳基硼酸酯络合物进行的,这引发了1,2-从硼向碳原子的迁移。中间体硼酸酯的随后氧化以良好的产率提供了杂联二芳基。已经进行了全面的11 B NMR研究以支持该机理。在没有过渡金属的情况下,两个亲核交叉偶联伙伴之间的交叉偶联显示了可靠的歧管,可以以高收率获得杂二芳基。呋喃,噻吩,苯并呋喃,苯并噻吩和吲哚等各种杂环具有良好的耐受性。最后,
One-pot synthesis of 2-substituted benzo[b]furans via Pd–tetraphosphine catalyzed coupling of 2-halophenols with alkynes
作者:Rong Zhou、Wei Wang、Zhi-jie Jiang、Kun Wang、Xue-li Zheng、Hai-yan Fu、Hua Chen、Rui-xiang Li
DOI:10.1039/c4cc00815d
日期:——
A catalyst composed of [Pd(η(3)-C3H5)Cl]2 and N,N,N',N'-tetra(diphenylphosphinomethyl)pyridine-2,6-diamine (L) was found to be effective for one-pot synthesis of 2-substitutedbenzo[b]furansfrom 2-halophenols and alkynes. For 2-bromo-3-hydroxypyridine, the catalyst loading could be as low as 1 ppm and the turnover number (TON) was up to 870,000.