An improved, efficient route to 2,2-difluoroethenylbenzenes
摘要:
Treatment of vinylidene fluoride with tert-BuLi at - 115 degrees C gave a solution of [F2C=CHLi]. Addition of Bu3SnCl to this lithium reagent at - 110 degrees C gave an 88% isolated yield of F2C=CHSnBu3. Reaction of F2C=CHSnBu3 with substituted aryl iodides under Stille-Liebeskind conditions [Pd(PPh3)(4)/Cu(I)I] at room temperature afforded the 2,2-difluoroethenylbenzines in good yield. In the absence of the Cu(I)I co-catalyst, no reaction occurred. This work provides the most efficient route for the conversion of aryl halides to 2,2-difluorostyrenes. (C) 2011 Elsevier B.V. All rights reserved.
which otherwise are essentially reluctant towards F‐nucleoplilic addition, now readily participate in this fluoroallylation reaction. Furthermore, this strategy provides an elegant example for the generation, as well as functionalization, of α‐CF3‐substituted benzylic radical intermediates using cheap and readily available starting materials.
Direct Vinylation and Difluorovinylation of Arylboronic Acids Using Vinyl- and 2,2-Difluorovinyl Tosylates via the Suzuki−Miyaura Cross Coupling
作者:Thomas M. Gøgsig、Lina S. Søbjerg、Anders T. Lindhardt、Kim L. Jensen、Troels Skrydstrup
DOI:10.1021/jo7027097
日期:2008.5.1
reaction conditions were developed for the Pd(0)-catalyzed Suzuki−Miyaura coupling reaction of aryl boronic acids with a simple electrophilic vinylation reagent, vinyl tosylate, providing access to styrene derivatives in good yields. The easilyaccessible vinyl tosylate represents a stable and less toxic alternative to the vinyl halides and the triflate/nonaflate derivatives. Furthermore, this methodology
Herein we present a novel strategy based on palladium-catalyzed allylic alkylation by taking advantage of the nucleophilic addition of external fluoride onto gem-difluoroalkenes as the initiation step. The merit of this protocol is highly appealing, as it enables a formal allylation of trifluoroethylarene derivatives through the in situ generation of β-trifluorocarbanions, which otherwise are deemed to
One-pot synthesis of gem-difluorostyrenes from benzyl bromide via olefination of phosphonium ylide with difluorocarbene
作者:Xiao-Yun Deng、Jin-Hong Lin、Ji-Chang Xiao
DOI:10.1016/j.jfluchem.2015.06.009
日期:2015.11
A new approach for the synthesis of gem-difluorostyrenes from benzyl bromide is described. Quaternization of triphenylphosphine with benzyl bromide to give phosphonium salts, deprotonation of the corresponding phosphonium salts to produce phosphonium ylide, and the subsequent olefination of phosphonium ylide with difluorocarbene generated from difluoromethylene phosphobetaine (Ph3P+CF2CO2−) by decarboxylation
描述了一种由苄基溴合成宝石-二氟苯乙烯的新方法。的三苯基膦与苄基溴,得到鏻盐,相应的鏻盐,以产生磷叶立德,并与二氟卡宾从二氟亚甲基磷酸酯生成鏻内鎓盐的后续烯的脱质子化(PH季铵化3 P + CF 2 CO 2 -可以发生通过脱羧)在一个锅中平稳地进行,以高收率提供最终的宝石-二氟苯乙烯。
Rhodium‐Catalyzed Defluorinative Vinylation of
<i>gem</i>
‐Difluoroalkenes for the Synthesis of 2‐Fluoro‐1,3‐dienes
we present a strategy for the formation of 2‐fluoro‐1,3‐diene derivatives via rhodium‐catalyzed direct C(sp2)—C(sp2) cross‐coupling of gem‐difluoroalkenes and acrylamides. By merging Rh(III)‐catalyzed C(sp2)–H bond activation and nucleophilic addition/F‐elimination of gem‐difluoroalkene, an efficient defluorinative vinylation reaction is uncovered, which leads to the generation of 2‐fluoro‐1,3‐dienes