Here we report the surprising discovery that high-energy vinyl carbocations can be generated under strongly basic conditions, and that they engage in intramolecular sp3 C–H insertion reactions through the catalysis of weakly coordinating anion salts. This approach relies on the unconventional combination of lithium hexamethyldisilazide base and the commercially available catalyst, triphenylmethylium tetrakis(pentafluorophenyl)-borate. These reagents form a catalytically active lithium species that enables the application of vinyl cation C–H insertion reactions to heteroatom-containing substrates.

A mild method for the synthesis of 2-quinolinones via hydroarylation of N-aryl alkynamides is reported. While traditional methods have relied on the use of strong Brønsted or Lewis acids, this report describes the development of mild reaction conditions that yield 2-quinolinones in good to excellent yield using a commercially available gold catalyst. Substrates bearing a variety of functional groups are presented, with N-substitution proving to be key to the reactivity of several substrates.

From the preparation of pharmaceuticals to enzymatic construction of natural products, carbocations are central to molecular synthesis. Although these reactive intermediates are engaged in stereoselective processes in nature, exerting enantiocontrol over carbocations with synthetic catalysts remains challenging. Many resonance-stabilized tricoordinated carbocations, such as iminium and oxocarbenium ions, have been applied in catalytic enantioselective reactions. However, their dicoordinated counterparts (aryl and vinyl carbocations) have not, despite their emerging utility in chemical synthesis. We report the discovery of a highly enantioselective vinyl carbocation carbon–hydrogen (C–H) insertion reaction enabled by imidodiphosphorimidate organocatalysts. Active site confinement featured in this catalyst class not only enables effective enantiocontrol but also expands the scope of vinyl cation C–H insertion chemistry, which broadens the utility of this transition metal–free C(sp 3 )–H functionalization platform.

A catalytic redox-neutral method for the synthesis of spirolactams proceeding through the dearomative spirocyclization of N-aryl alkynamides is reported. In contrast to stoichiometric activating agents employed for related transformations, we show that the use of 5 mol % of Au(PPh)Cl and AgOTf in dichloroethane at 50-80 °C leads to selective spirocyclization, furnishing the products in yields of 35-87%. The substrate scope of the reaction is good, with both electron-donating and electron-withdrawing groups being tolerated around the arene ring, as well as substitution at the amide nitrogen. The identity of the para-alkoxy group on the arene ring is key to achieving selectivity for spirocyclization over alternative mechanistic pathways. While the presence of a para-methoxy group leads to trace amounts of the desired spirolactams, the para-tert-butoxy or para-hydroxy substrate analogues furnish the spirolactams in good yield with high selectivity.

<p>Here we report the surprising discovery that high-energy vinyl carbocations can be generated under strongly basic conditions, and that they engage in intramolecular sp3 C–H insertion reactions through the catalysis of commercially available weakly coordinating anion salts. This approach relies on the unconventional combination of lithium hexamethyldisilazide base and the commercially available catalyst, triphenylmethylium tetrakis(pentafluorophenyl)borate. These reagents form a catalytically active lithium species that enables the application of vinyl cation C–H insertion reactions to heteroatomcontaining substrates.</p>

Mit Jodathyl kann ein athylirtes nicht krystallisirbares Da die Base nach der Gleichung Product erhalten werden. 3(CioH1,02. XH,)-2. NH, = C,oI&,NO, entsteht , also dem unbelrannten Triamylenoxyd-Amnionial~ isoiner ist, so bezeichnet sie der Verf. mit clcm Naiiicn Trianzyli~leriozyil-AmmoninX' und lasst die Wahl zwischen den beiden rationellen Fornieln in beiden Fallen ist es nach H o f m a n n ' s Ausdrucksweise eine tertiare Monoaminbase.

La!ne and Williams. 2983 578. Organic Complex -forming Agents for Metals. Phrt II.* Preparation of 5-Hydroxy-and 5 : 8-Dihydroxy-quinoxalines and Related Compounds.By E. S. LANE and C. WILLIAMS.5-Hydroxy-and 5 : 8-dihydroxy-quinoxalines containing a variety of 2-and 3-substituents have been prepared by dealkylation of the corresponding 6-methoxy-and 5 : 8-diethoxy-quinoxalinesJ and characterised as the acetyl derivatives.

Novel trisubstituted ethylenes, ring-substituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH=C(CN)CO2C3H7 (where R is 2,3,6-trichloro, 2,3,4-trifluoro, 2,3,5-trifluoro, 2,4,5-trifluoro, 2,4,6-trifluoro, 3,4,5-trifluoro) were prepared by the piperidine catalyzed Knoevenagel condensation of ring-trisubstituted benzaldehydes and propyl cyanoacetate. The ethylenes when copolymerized with styrene in solution with radical initiation (ABCN) at 70&deg;C resulted in formation of copolymers. The composition of the copolymers was calculated from nitrogen analysis. The structures and properties were characterized by IR, 1H and 13C-NMR, GPC, DSC, and TGA.