通过使用单齿瞬时导向基团策略和钯催化的组合,成功地实现了 α-酮酯的前所未有的直接邻位C-H 芳基化和氯化。原位形成的亚胺将α-酮酯的双齿配位模式改变为单齿配位,从而实现邻位C-H活化。重要的是,由乙酸根阴离子桥接的关键双核环钯中间体通过 X 射线衍射得到了明确的特征,这有力地支持了所提出的机制。实用性进一步描述为通过随后的两步衍生化轻松获得口服抗血小板药物氯吡格雷消旋体。
通过使用单齿瞬时导向基团策略和钯催化的组合,成功地实现了 α-酮酯的前所未有的直接邻位C-H 芳基化和氯化。原位形成的亚胺将α-酮酯的双齿配位模式改变为单齿配位,从而实现邻位C-H活化。重要的是,由乙酸根阴离子桥接的关键双核环钯中间体通过 X 射线衍射得到了明确的特征,这有力地支持了所提出的机制。实用性进一步描述为通过随后的两步衍生化轻松获得口服抗血小板药物氯吡格雷消旋体。
Ethyl dichloro(ethoxy)acetate (1) and methyl dichloro(methoxy)acetate (2) were characterized. The reaction of 1 and 2 with aromatics in the presence of AlCl3 gave a considerable yield of aromatic α-keto ester. The aromatics included mono- and polymethylbenzene and anisol. The reaction was studied under various conditions and the results were compared with the acylation by ethoxalyl or methoxalyl chloride
One-Pot Tandem Assembly of Amides, Amines, and Ketones: Synthesis of C4-Quaternary 3,4- and 1,4-Dihydroquinazolines
作者:Molly V. Campbell、Alexei V. Iretskii、R. Adam Mosey
DOI:10.1021/acs.joc.0c01308
日期:2020.9.4
the synthesis of diverse C4-quaternary 3,4-dihydroquinazolines fromamides, amines, and ketones has been developed. The one-pot reaction involves successive triflic anhydride mediated amide dehydration, ketimine addition, and Pictet–Spengler-like cyclization processes and affords products in up to 92% yield. Conversion of 3,4-dihydroquinazolines to the corresponding 1,4-dihydroquinazolines via a two-step
compounds such as aroylformates, α-diketones, and isatins with arylazocarboxylates has been developed for a facile synthesis of N-aryl-N-acyl hydrazones in moderate to excellent yields under very mild conditions. Mechanistic investigation based on 31P NMR tracking experiments unveils that the reaction is initiated with the in situ formation of the modified Huisgen zwitterions from arylazocarboxylates and PPh3