Transition-Metal-Free Tunable Chemoselective N Functionalization of Indoles with Ynamides
作者:Alexandre Hentz、Pascal Retailleau、Vincent Gandon、Kevin Cariou、Robert H. Dodd
DOI:10.1002/anie.201402767
日期:2014.8.4
Two unprecedented Nfunctionalizations of indoles with ynamides are described. By varying the electron‐withdrawing group on the ynamide nitrogen atom, either Z‐indolo‐etheneamides or indolo‐amidines can be selectively obtained under the same metal‐free reaction conditions. The scope and synthetic potential of these reactions, as well as some mechanistic insights provided by DFT calculations, are reported
Ynamides are versatile buildingblocks in organic synthesis. However, the synthesis of amino acid-derived ynamides is difficult but in high demand. Herein, we disclose the copper-catalyzed Csp-N coupling of sulfonamide, including amino acid and peptidederivatives, to give ynamides by using alkynyl benziodoxolones with broad functional group tolerance under mild reaction conditions. The electron-rich
The yields of ynamides using Hsung's second generation protocol depend substantially on the quality of K3PO4. of K3PO4 from different suppliers were investigated by various techniques, revealing that the use Of pure and anhydrous K3PO4 provides higher ynamide yields in comparison to samples contaminated with hydrates (K3PO4 center dot 1.5H(2)O and K3PO4 center dot 7H(2)O). With high quality K3PO4, a number of ynamides were synthesized in yields of 52-91%. In addition. we report that ynamides can undergo regioselective hydroamination with carbamates.