Micellar-System-Mediated Direct Fluorination of Ketones in Water
作者:Stojan Stavber、Gaj Stavber、Marko Zupan
DOI:10.1055/s-0028-1087924
日期:2009.3
A micellar system was developed and applied for direct regioselective fluorination of a variety of cyclic and acyclic ketones to α-fluoroketones in water as reaction medium with Selectfluor F-TEDA-BF 4 as fluorinating reagent. The inexpensive ionic amphiphile sodium dodecyl sulfate (SDS) was found to be an excellent promoter for fluorofunctionalization of hydrophobicketones without prior activation
Elemental fluorine. Part 19: Electrophilic fluorination of hexyl derivatives bearing electron withdrawing groups
作者:Richard D. Chambers、Mandy Parsons、Graham Sandford、Emmanuelle Thomas、Jelena Trmcic、John S. Moilliet
DOI:10.1016/j.tet.2006.03.113
日期:2006.7
Reaction of a series of model hexyl derivatives of the form C6H13–X (X=Cl, Br, I, CO2Me, COMe, CHO) with both elemental fluorine and Selectfluor™ was studied in order to assess the impact of electron withdrawing functional groups upon fluorination of an alkyl chain. Fluorination generally occurs at secondary sites, with a slight preference for those that are furthest removed from the electron withdrawing
研究了一系列形式为C 6 H 13 –X(X = Cl,Br,I,CO 2 Me,COMe,CHO)的模型己基衍生物与元素氟和Selectfluor™的反应,以评估氟的影响。烷基链氟化时的吸电子官能团。氟化通常发生在次要位置,与亲电子取代过程一致,略微偏爱从吸电子基团离得最远的位置,尽管在大多数情况下会获得氟化产物的混合物。
Chelation-Controlled Diastereoselective Reduction of α-Fluoroketones
作者:Pramod K. Mohanta、Todd A. Davis、Jeremy R. Gooch、Robert A. Flowers
DOI:10.1021/ja052546x
日期:2005.8.1
The effect of Ti-based Lewis acids on the reduction of alpha-fluoropropiophenone was examined to determine whether chelation control could be used to direct the diastereoselectivity of conversion to an alpha-fluoro alcohol. Pretreatment of alpha-fluoropropiophenone with TiCl4 followed by reduction with LiBH4 in diethyl ether or methylene chloride provided the syn diastereomer predominantly, while use of Ti(OiPr)4 under identical conditions provided the anti diastereomer as the major product. The products are consistent with a chelation-controlled mechanistic pathway in the former reduction and a nonchelation pathway in the latter case. Detailed 1H, 13C, and 19F NMR studies were consistent with chelation between TiCl4 and alpha-fluoropropiophenone under the reaction conditions utilized in this study. Reduction of other alpha-fluoroketones in the presence of TiCl4 also provided a high degree of diastereoselectivity in the conversion to alpha-fluoro alcohols, showing the generality of this approach.