The transition-metal-catalyst-free oxidative homocoupling of organomanganese reagents prepared by the insertion of magnesium into organic halides in the presence of MnCl2·2LiCl
substitution even in the presence of strong electron‐donating groups and enables de‐tert‐butylation required for the complete annulation. Also demonstrated is the applicability of the method to introduce five‐, six‐, and seven‐membered rings containing oxygen, whereas multiple annulations also open up a short synthetic path to ladder‐type O‐heteroacenes and oligodibenzofurans.
Thieme Journal Awardees - Where Are They Now? On Cobalt-Catalyzed Biaryl Coupling Reactions
作者:Axel Jacobi von Wangelin、Matthias Mayer、Waldemar Czaplik
DOI:10.1055/s-0029-1218013
日期:2009.11
An operationally simple biaryl coupling reaction has been developed. The underlying domino process involves in situGrignard formation from aryl bromides and subsequent homocoupling with catalytic CoCl 2 and I bar synthetic air as terminal oxidant.
已开发出操作简单的联芳基偶联反应。潜在的多米诺骨牌过程涉及由芳基溴化物原位形成格氏,随后与催化 CoCl 2 和 I bar 合成空气作为末端氧化剂均偶联。
Homocoupling of Arylboronic Acids Catalyzed by a Simple Hydrophilic Palladium(II) Complex in Aqueous Media
Homocoupling of arylboronic acids has been successfully carried out by using the inexpensive hydrophilic palladium(
II) complex PdCl2(NH2CH2COOH)2 as catalyst in i-PrOH/H2O (v/v=1:2) under aerobic atmosphere without elevated
heating to give rise to symmetrical biaryls in moderate to good yields. The aqueous media, room temperature reaction
and the low amounts of catalyst (0.5 mol%) show a practical and environmentally benign protocol. In addition, enhancement
of yield was observed in the presence of 0.5 equiv. p-toluenesulfonyl chloride. Furthermore, the byproducts of
this reaction were not observed while biaryl is the only product, which results in much more facile in the separation of the
product symmetrical biaryls from arylboronic acids.
The transition-metal-catalyst-free oxidative homocoupling of organomanganese reagents prepared by the insertion of magnesium into organic halides in the presence of MnCl<sub>2</sub>·2LiCl
作者:Zhihua Peng、Na Li、Xinyang Sun、Fang Wang、Lanjian Xu、Cuiyu Jiang、Linhua Song、Zi-Feng Yan
DOI:10.1039/c4ob01235f
日期:——
An oxidative homocoupling of organomanganese reagents was performed in one pot without an additional transition-metal catalyst.