Regio- and stereoretentive synthesis of branched, linear (E)- and (Z)-allyl fluorides from allyl carbonates under Ir-catalysis
Regio- and stereoretentive synthesis of branched, linear (E)- and (Z)-allyl fluorides from allyl carbonates under Ir-catalysis
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DOI：
10.1039/c2sc21789a
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发表时间：
2013-01-01
期刊：
影响因子：
8.4
通讯作者：
Gouverneur, Veronique
中科院分区：
文献类型：
--
作者：
Benedetto, Elena;Tredwell, Matthew;Gouverneur, Veronique
本文介绍了一种新的碳酸烯丙酯区域和立体控制合成的催化方法。该转化使用TBAF中心点4 tBuOH作为氟化物源和[Ir（COD）Cl]（2）作为催化剂;最常用的[Ir（COD）Cl]（2）/亚磷酰胺体系无效。在合成上，该反应的特征在于从底物到产物的高度结构保守性。（E）-烯丙基碳酸酯的缩合导致线性（E）-烯丙基氟化物（l：B > 20：1，E：Z > 20：1）是前所未有的，并且是氟化物作为亲核试剂的独特特征。本发明公开了过渡金属催化的缩合反应的第一个实例，该实例提供了（Z）-烯丙基氟化物（Z：E比>= 20：1），同时沿着了在[Ir（COD）Cl]存在下用[F-18]氟化物成功地缩合支链、直链（E）-和（Z）-烯丙基碳酸酯（2）。O-18-反应物的标记揭示了烯丙基电离步骤中的内部返回，以及有效的分子内和分子间同位素交换的途径。
This paper describes a new catalytic method for the regio- and stereocontrolled fluorination of allylic carbonates. This transformation uses TBAF center dot 4tBuOH as the fluoride source and [Ir(COD)Cl](2) as the catalyst; the most commonly used [Ir(COD)Cl](2)/phosphoramidite system is ineffective. Synthetically, this reaction is characterized by a high degree of structural conservation in going from substrates to the products. The fluorination of (E)-allylic carbonates leading to linear (E)-allylic fluorides (l : b > 20 : 1, E : Z > 20 : 1) is unprecedented and a unique feature of fluoride as the nucleophile. The first examples of transition metal catalyzed fluorination affording (Z)-allyl fluorides (Z : E ratio >= 20 : 1) are disclosed along with the successful fluorination of branched, linear (E)- and (Z)-allyl carbonates with [F-18] fluoride in the presence of [Ir(COD)Cl](2). O-18-Labeling of the reactant reveals internal return during the allylic ionization step, and pathways for effective intra-and intermolecular isotope exchange.