Design and synthesis of condensed thienocoumarins by Suzuki–Miyaura reaction/lactonization tandem protocol
摘要:
A concise and efficient approach to a series of chromen-4-ones with fused thiophene ring has been developed using the Suzuki-Miyaura reaction of bromothiophene-2- and 3-carboxylates with 2-methoxyboronic acids and subsequent cyclization of prepared alkyl (2-methoxy)aryl thiophene-2- and 3-carboxylates under the action of BBr3/KOtBu. Starting bromothiophenes are easily obtained from corresponding commercially available aminothiophenes by diazotization/bromination reaction. (C) 2012 Elsevier Ltd. All rights reserved.
2-甲酯基噻吩-3-重氮四氟硼酸盐的钯催化的松田-的Heck和Suzuki-Miyaura交叉偶联1进行到合成一系列在β位官能噻吩衍生物。使用乙酸钯[Pd(OAc)2 ],一种无配体的钯催化剂,无碱,在室温下,好氧条件下,反应时间短的情况下,可获得良好或优异的交叉偶联产物收率。重氮化和交叉偶联的序列也可以在一锅法中进行,从而避免了噻吩并重氮盐衍生物的分离。此外,2-甲氧基羰基苯并[ b ]噻吩-3-重氮四氟硼酸盐8 通过应用相同的Suzuki-Miyaura优化反应条件也可以有效地芳基化。