A facile and efficient one‐pot synthesis of isoxazol‐3(2H)‐ones has been developed starting from α‐acyl cinnamides and tosyliminophenyliodinane catalyzed by copper(II) acetate [Cu(OAc)2] under very mild conditions involving a tandem aza‐Michael addition and intramolecular cyclization sequence.
A copper‐catalyzed cascade reaction involving trifluoromethylation of acrylamides coupled with ring closure and indole dearomatization is reported. This facile transformation was highly regioselective and proceeded under mild conditions, allowing efficient access to trifluoromethyl‐substituted spiro[indole‐3,3′‐pyrrolidine] derivatives, which are of increasing interest to the pharmaceutical industry.
The first highly enantioselective formal [4+2] tandem cyclizations between isatylidenemalononitriles and activated dienes catalyzed by bifunctional chiral phosphine catalysts have been developed, yielding multistereogenic spirocyclic oxindoles in high yields and excellent optical purity. This reaction is accomplished via a tandem Rauhut–Currier/Michael/Rauhut–Currier reaction sequence.
Nine types of diversely fused heterocyclic quaternary ammonium salts were constructed through an oxidative C H annulation reaction. Both high‐valent pentamethylcyclopentadienylcobalt(III) and pentamethylcyclopentadienyliridium(III) were found to be effective as catalyst for this reaction. Broad substrate scope and good functional group tolerance were observed.
Pyrroles, ubiquitous bioactive heterocycles in nature, are readily prepared via a palladium‐catalyzed oxidative annulation of cyclic trans‐enamines to various internal alkynes in the absence of a directing group.
The 8‐aminoquinoline‐directed, nickel(II)‐mediated ortho‐iodination of benzamides using molecular iodine has been developed. The process is highly regioselective and furnishes only monoiodinated products. A broad range of arenes and heteroarenes with diverse functional groups provided monoiodinated products in good to excellent yields.
A synthetic strategy has been developed for the synthesis of 2‐dialkylaminoquinolines from easily available quinoline N‐oxides, tertiary amines, diisopropyl H‐phosphonate and carbon tetrachloride (CCl4) in one pot under metal‐free conditions at room temperature.
This paper describes the aerobic oxidation of styrenes catalyzed by iron(III) chloride (FeCl3) to form β‐keto‐N‐alkoxyphthalimides in fair to good yields. This oxidative process employs mild conditions with green and atom efficient dioxygen (O2) as the oxidant.
The first active aza analogue of narciclasine was synthesized from a pentasubstituted derivative of nicotinic acid. The key features of the synthesis include a halogen dance of bromopyridine and an intramolecular Heck reaction with a conduramine derived chemoenzymatically from bromobenzene. 10‐Aza‐narciclasine was found to have reasonable activity against several cancer cell lines.
A copper(I)‐catalyzed, (diacetoxyiodo)benzene [PhI(OAc)2]‐mediated ring‐expansion/thiolactonization of α‐oxo ketene dithioacetals was efficiently realized via azidation of the internal olefinic C−H bond with sodium azide under mild conditions. Sequential amination, ring‐expansion rearrangement, and thiolactonization occurred to form aminated thiolactones in the presence of acetic anhydride as the additive, while only C−H amination to afford the unprotected enamines occurred when using ammonium sulfide as a reducing additive. The in situ generated vinyl azides were confirmed as the reactive intermediates, which were captured by phenylacetylene to produce triazoles. This protocol provides a concise route to thiolactone derivatives and unprotected enamines.
An efficient protocol for the copper‐mediated trifluoromethylthiolation of heteroaryl bromides has been achieved using the copper complex (bpy)Cu(SCF3) as trifluoromethylthiolating reagent. This procedure provides a straightforward synthetic method for heteroaryl trifluoromethyl sulfides from readily available, simple starting materials. The reaction demonstrates a broad substrate scope and tolerates a wide array of functional groups, including nitrile, ester, chloro, nitro, or methoxy substituents.
Inspired by the bulkier bis(triphenylphosphine)–silver cation‐induced mechanism of propargylic alcohols and carbon dioxide through the alkyl carbonate intermediate, a robust dual‐component catalytic system consisting of silver acetate and tetraheptylammonium bromide was rationally developed for the synthesis of α‐methylene cyclic carbonates under ambient conditions without employing any additional organic base and ligand. This is one of the most effective catalysts reported to date for this conversion, with a very high turnover number of up to 6024, probably due to the synergistic effect of Lewis basic and Lewis acidic species for the activation of both propargylic alcohol and carbon dioxide by the formation of the alkyl carbonate with a bulkier counterion. Notably, this catalyst also worked well for the carboxylative cyclization of propargylic amines with carbon dioxide with the highest turnover number of 544.
