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Just Released - Fluorous DIAD!
Use F-DIAD with fluorous triphenylphosphine for a fully solution-phase Mitsunobu reagent system that also allows simple removal of both the phosphine oxide and the hydrazine by-products. FTI now offers this second generation fluorous azodicarboxylate with superior performance in the Mitsunobu conversion of phenols and other higher base strength nucleophiles, as well as lower pKa nucleophiles like carboxylic acids and imides. It is now possible to adapt nearly any Mitsunobu reaction to fluorous methods, combining powerful bond forming capabilities with the speed and ease of fluorous separations across a broad spectrum of substrates. As seen in the FTI generated table below, F-DIAD has a reaction profile very similar to traditional DEAD. Based on extensive and highly valued customer feedback, it became clear that the F-DEAD currently in our catalog did not fully mirror the behavior of the traditional DEAD in all Mitsunobu reactions. The F-DIAD was developed to overcome these limitations. For additional information or pricing, please contact Kris Mikulan and refer to catalog #026100. Also recently updated is the Fluorous Mitsunobu Application Note.
Fluorous Chemistry in Buchwald-Hartwig Aminations
R. Jason Herr et al of Albany Molecular Research, Inc. recently reported the use of a fluorous benzophenone imine, F-BPI, in the Buchwald-Hartwig amination of aryl halides. In their report a variety of both electron rich and electron deficient aryl halides 1 were successfully coupled under Pd catalysis with F-BPI to provide N-arylimines 2. These were then hydrolyzed to afford the desired anilines 3 in overall good to excellent yields and excellent purities. Both 2 and 3 were purified by fluorous solid phase extraction (F-SPE) to provide products in >95% purity with yields similar to that achieved using benzophenone imine. The use of fluorous techniques allowed for the fast and reliable purification for all examples of both 2 and 3 using a single purification method. As observed with other fluorous reagents the addition of the fluorous domain provides a handle for purification without affecting the reactivity of the original reagent.
ref: Cioffi, C.L.; Berlin, M.L.; Herr, R.J. Synlett, 2004, 841
Phase Vanishing Reactions in a Test Tube!
Phase vanishing is a unique technique that slowly mixes two reactants in a test tube. It is very simple and there is no need to use a syringe pump or an addition funnel. A fluorous solvent, such as FC-72, plays a key role in this technique to initially separate the two reactants, yet it allows them to react slowly. This technique was introduced by Professor Ryu and coworkers in Japan in 2002, who demonstrated various halogenation reactions by this method (Ryu, I. et al. J. Am. Chem. Soc. 2002, 124, 12946). For example, bromination of olefins can be done by adding bromine, FC-72, and an olefin in a test tube. Eventually all of the bromine diffuses up through FC-72 to the olefin layer to give the corresponding brominated products (Figure A). The name ‘phase vanishing' came from the fact that one of the phases (in this case, the bromine layer) disappears at the end of the reaction.
Recently, Jana and Verkade reported oxidation of alkenes, amines, and sulfides by mCPBA using the phase vanishing method (Jana, N.K.; Verkade, J. F. Org. Lett . 2003, 5, 3787). In a test tube, they put mCPBA in dibromoethane (DBE, bottom layer), FC-72 (middle layer), and a sulfide in dichloromethane (DCM, top layer) (Figure B). Eventually, the DCM layer disappeared to give the product in the bottom layer (DCM + DBM). In this reaction, both substrate (sulfides) and the reagent (mCPBA) have very poor solubility in FC-72; however, the reaction proceeded within 2 days. Professor Curran and postdoc Werner in Pittsburgh studied the mechanism of this phase vanishing reaction using an organic dye to trace the phase vanishing process (Curran, D.P.; Werner, S. Org. Lett. 2004, 6, 1021). According to their experiments, both organic solvents will diffuse into each other through FC-72, and after a certain time, the top layer (DCM + DBM) becomes heavier than FC-72, thus causing the top layer to ‘drop' into the bottom layer. Because of its simpleness, one potential use of phase vanishing technique is parallel synthesis. Here a large number of compounds, in which simultaneous slow additions of reactive reagents can be made to a large number of reaction vessels, thus simplifying what could be a challenging task.
FTI Website - Continually Updated
Take a few minutes to visit the Fluorous Technologies website, www.fluorous.com, to learn more about our products. Our website contains our on-line catalog which is continually updated to include new products and the FTI product selection guide to guide you to the fluorous product best suited for your desired application. You will also find Application Notes for many of the FluoroFlash® reagents and sorbents as well as references to publications pertinent to fluorous technology, many of which were written by our chemists. While on the website, please complete the brief registration survey which will allow us to deliver the right information to you.