A catalyst generated from Pd(dba)(2) and the bulky electron-rich phosphine ligand 2-(dicyclohexylphosphino)-2',4', 6'-tri-i-propyl-1 - 1'-biphenyl is effective for the alpha-arylation of oxindoles. Generation of the potassium-enolates of a range of oxindoles allows coupling with aryl chlorides, bromides, and triflates. Significant variation of the substitution pattern on both the oxindole and aryl halide is possible.
Enantioselective Synthesis of Oxindole‐Derived α‐Aryl‐β‐Amino Acid Derivatives and δ‐Lactams with Homophthalic Anhydrides
作者:Zhixin Chang、Can Ye、Junfeng Fu、Paidamoyo Chigumbu、Xiaofei Zeng、Yongjiang Wang、Chengjun Jiang、Xiaoyu Han
DOI:10.1002/adsc.201901074
日期:2019.12.17
A highly diastereo‐ and enantioselective Mannich reaction of isatin‐derived N‐Boc imines with homophthalic anhydrides is disclosed for the first time, which allows the direct synthesis of a wide range of oxindole‐derived α‐aryl‐β‐amino acids with two adjacent carbon stereogenic centers in a highly stereoselective fashion (up to >95:5 dr & >99% ee). The resulted Mannich adducts can be easily converted
pyrazoloquinazolinone derivatives. The strategy involves a one-pot reaction wherein the N-tosylhydrazone and its corresponding diazo derivative are generated in situ, followed by an intramolecular 1,3-dipolar cycloaddition–ring expansion to provide the pyrazolo-[1,5-c]quinazolinone motif. This approach enables straightforward access to a diverse range of highlyfunctionalized N-heterocyclic compounds
我们开发了一种无过渡金属的方法来构建吡唑并喹唑啉酮衍生物。该策略涉及一锅反应,其中原位生成N-甲苯磺酰腙及其相应的重氮衍生物,然后进行分子内 1,3-偶极环加成环扩展以提供吡唑并-[1,5- c ]喹唑啉酮基序。这种方法能够以良好的产率(高达 92%)直接获得各种高度功能化的 N-杂环化合物。