Atom-economic generation of gold carbenes: gold-catalyzed formal [3+2] cycloaddition between ynamides and isoxazoles

Abstract

An unprecedented gold-catalyzed formal [3+2] cycloaddition between ynamides and isoxazoles has been developed, allowing rapid and practical access to a wide range of synthetically useful 2-aminopyrroles.

Anthranil: An Aminating Reagent Leading to Bifunctionality for Both C(sp3)−H and C(sp2)−H under Rhodium(III) Catalysis

“…[13] Despite this success,t he system is limited to simple amidation. [15] Significantly,a mination using anthranils could deliver an ucleophilic amino group tethered to an electrophilic formyl group,w hich can be hard to introduce, and the formyl group may experience compatibility issues in many coupling systems. We reasoned that anthranil may serve this purpose in that it is sufficiently coordinating [14] and the N À Ob ond is polarized and cleavable.…”

Gold‐Catalyzed [4+2] Annulation/Cyclization Cascades of Benzisoxazoles with Propiolate Derivatives to Access Highly Oxygenated Tetrahydroquinolines

“…Quinoline oxides (3)a re versatile intermediates for delivering oxygenated quinoline derivatives because of their epoxide functionality.A ss hown in Scheme 1, LiAlH 4 reductions of 3a afforded the alcohol 8a as as ingle diastereomer, and the structure of this diol derivative was determined by 1 HNOE spectroscopy.R emoval of the epoxide in 3a was achieved with Pd/C/H 2 in MeOH, thus yielding the quinoline derivative 3a H in 75 %yield. Ther eactions were also compatible with various benzisoxazoles substituted with X = Cl, Br, and OCO 2 Et, as well as Y = Cl, and the corresponding products 7f-i were obtained efficiently (entries [5][6][7][8]. Particularly notable is Zn(OTf) 2 -catalyzed hydrative cyclizations of 3a in DCE.…”

“…[4] Thec urrent syntheses of these bioactive molecules rely on diverse and long procedures. [6] Theu se of NÀOcontaining nucleophiles is av iable route to access valuable azacyclic frameworks.T he groups of Ye [7] and Hashmi [8] reported interesting [3+ +2] annulations of isoxazoles and benzisoxazoles with electron-rich ynamides,t hereby yielding substituted pyrrole derivatives chemoselectively [ Figure 2, Eq. [6] Theu se of NÀOcontaining nucleophiles is av iable route to access valuable azacyclic frameworks.T he groups of Ye [7] and Hashmi [8] reported interesting [3+ +2] annulations of isoxazoles and benzisoxazoles with electron-rich ynamides,t hereby yielding substituted pyrrole derivatives chemoselectively [ Figure 2, Eq.…”

Sulfilimine als vielseitige Nitrentransfer‐Reagenzien: Einfacher Zugang zu vielfältigen aza‐Heterocyclen

“…Insbesondere die Generierung von Goldcarbenen aus Alkinen über intra-und intermolekulare Atomtransferprozesse und nachfolgendes Abfangen solcher Carbene hat sich zu einem erfolgreichen Synthesewerkzeug füre ffiziente Tr ansformationen entwickelt. Im Gegensatz dazu erweitert der inter-o der intramolekulare Nitrentransfer nukleophiler Nitrenäquivalente,w ie pyridinbasierte aza-Ylide, [4] Azide, [5] 2H-Azirine [6] und Isoxazolderivate, [7] sowie der Carbentransfer aus Sulfoniumyliden, [8] die Mçglichkeiten zur Ringbildung. Im Gegensatz dazu erweitert der inter-o der intramolekulare Nitrentransfer nukleophiler Nitrenäquivalente,w ie pyridinbasierte aza-Ylide, [4] Azide, [5] 2H-Azirine [6] und Isoxazolderivate, [7] sowie der Carbentransfer aus Sulfoniumyliden, [8] die Mçglichkeiten zur Ringbildung.…”