School of Biological and Chemical Sciences, Queen Mary University of London , Joseph Priestley Building, Mile End Road, E1 4NS, London, U.K.
J Am Chem Soc. 2014 Mar 19;136(11):4109-12. doi: 10.1021/ja500457s. Epub 2014 Mar 11.
The direct functionalization of phenols at the ortho and para position is generally facilitated by the electron-donating nature of the hydroxyl group. Accessing meta-functionalized phenols from the parent phenols, on the other hand, generally requires lengthy synthetic sequences. Here, we report the first methodology for the one-pot direct meta-selective arylation of phenols. This methodology is based on a traceless directing group relay strategy. In this process carbon dioxide is used as a transient directing group which facilitates a palladium catalyzed arylation meta to the phenol hydroxyl group with iodoarenes. This transformation proceeds with complete meta-selectivity and is compatible with a variety of functional groups both in the phenol and in the iodoarene coupling partner.
酚类化合物在邻位和对位的直接官能化通常得益于羟基的供电子性质。另一方面，从母体酚类化合物中获得间位官能化的酚类化合物通常需要冗长的合成序列。在这里，我们报告了酚类化合物的一锅法直接间位选择性芳基化的首例方法。该方法基于无痕迹导向基团接力策略。在此过程中，二氧化碳被用作瞬态导向基团，它促进了钯催化的间位芳基化反应，芳基碘化物与酚羟基反应。该转化具有完全的间位选择性，并且与酚和碘芳烃偶联伙伴中的各种官能团兼容。
