已开发出一种微波辅助的氟合成路线,用于 3-氨基-1,2-苯并恶唑和4-氨基-1 H -2,3-苯并恶嗪。该策略包括将各自的2-氟苄腈或2-(溴甲基)苄腈与氟肟标签连接,得到芳基肟中间体,然后将其进行环化,同时在酸性条件下将底物标签裂解,从而提供所需的产物,中等至中等产量。另外,可以使芳基肟中间体进一步反应以扩展化合物库。可以使用氟固相萃取(F-SPE)轻松分离产物,回收的氟酮可以转化回氟肟,并在下一轮合成中重复使用。
Fluorous Oxime Palladacycle: A Precatalyst for Carbon–Carbon Coupling Reactions in Aqueous and Organic Medium
作者:Woen Susanto、Chi-Yuan Chu、Wei Jie Ang、Tzyy-Chao Chou、Lee-Chiang Lo、Yulin Lam
DOI:10.1021/jo202482h
日期:2012.3.16
To facilitate precatalyst recovery and reuse, we have developed a fluorous, oxime-based palladacycle 1 and demonstrated that it is a very efficient and versatile precatalyst for a wide range of carbon carbon bond formation reactions (Suzuki-Miyaura, Sonogashira, Stille, Heck, Glaser-type, and Kumada) in either aqueous or organic medium under microwave irradiation. Palladacycle 1 could be recovered through F-SPE in various coupling reactions with recovery ranging from 84 to 95% for the first cycle. Inductively coupled plasma optical emission spectrometry (ICP-OES) analyses of the Pd content in the crude product from each class of transformation indicated extremely low levels of leaching and the palladacycle could be reused four to five times without significant loss of activity.
Expedient carbonylation of aryl halides in aqueous or neat condition
作者:Wei Jie Ang、Lee-Chiang Lo、Yulin Lam
DOI:10.1016/j.tet.2014.09.065
日期:2014.11
An expedient and versatile, microwave-assisted procedure for the carbonylation of aryl halides with boronic acids, alcohols or amines in water or under neat conditions has been developed. The reaction is catalyzed by fluorous, oxime-based palladacycle 1 that shows an excellent recyclable property and low levels of Pd leaching. To demonstrate the usefulness of the protocol, we applied it to the preparation of compounds of pharmaceutical interest, including a precursor of the reverse transcriptase inhibitor, niacin, benzocaine and butamben. (C) 2014 Elsevier Ltd. All rights reserved.