Nitrogen-containing Lewis bases catalyzed highly regio- and stereoselective reactions of allenyl acetates with isatin-derived oximes

Acetoxy allenoates as emerging synthons in annulation/cycloaddition reactions

In contrast to the normal allenoates (2,3-butadienoates) that undergo phosphine/amine addition generating dipolar-type intermediates, acetoxy allenoates that contain a facile-leaving -OAc group create electrophilic diene-phosphonium/ammonium intermediates rendering the reactivity pattern vastly different in the two cases. This review highlights the fascinating chemistry of acetoxy allenoates and related substrates. The diene-phosphonium/ammonium intermediate thus formed from acetoxy allenoate [substituted 5-acetoxypenta-2,3-dienoate or 2-(acetoxymethyl)buta-2,3-dienoate] participates in a plethora of cycloaddition/annulation reactions with bisnucleophiles generating multifunctional hetero- or homo-cycles in very few steps. Thus the electron-withdrawing effect of the phosphonium as well as carboxylate groups, making the diene-phosphonium/ammonium intermediates quite electrophilic, has been pivotal to the growth and significant interest during the last 10-15 years in this emerging class of substrates as revealed in this article. A comparison of this chemistry with that of (acetoxy)(acyl)allenes and allenyl acetates is also made briefly.

Metal-Involving Synthesis and Reactions of Oximes

This review classifies and summarizes the past 10-15 years of advancements in the field of metal-involving (i.e., metal-mediated and metal-catalyzed) reactions of oximes. These reactions are diverse in nature and have been employed for syntheses of oxime-based metal complexes and cage-compounds, oxime functionalizations, and the preparation of new classes of organic species, in particular, a wide variety of heterocyclic systems spanning small 3-membered ring systems to macroheterocycles. This consideration gives a general outlook of reaction routes, mechanisms, and driving forces and underlines the potential of metal-involving conversions of oxime species for application in various fields of chemistry and draws attention to the emerging putative targets.

Synthesis and Application of Phenyl Nitrone Derivatives as Acidic and Microbial Corrosion Inhibitors

Nitrone has drawn great attention due to its wide applications as a 1,3-dipole in heterocyclic compounds synthesis and the bioactivities. With the special structure, nitrone can also be used as ligand in inorganic chemistry. Based on the current research, the nitrones are anticipated to be effective inhibitors against acidic and microbial corrosion. The aim of this work is to investigate the inhibitory action of nitrones. In this work, a series of phenyl nitrone derivatives (PN) was synthesized and used as acidic and microbial corrosion inhibitors. The results indicate that several compounds show moderate to high inhibition efficiency (IE) in 3% HCl. Accompanied with HMTA or BOZ, the IEs greatly increase, and the highest efficiency of 98.5% was obtained by using PN4 + BOZ. Investigation of the antibacterial activity against oilfield microorganism shows that the nitrone derivatives can inhibit SRB, IB, and TGB with moderate to high efficiency under 1,000 mg/L, which makes them potential to be used as bifunctional oilfield chemicals.

Phosphine-mediated reaction of 3-methyl allenoate and isatins: a protocol for the synthesis of spirofuran oxindoles

A facile synthesis of spirofuran oxindoles via phosphine-mediated reaction of 3-alkyl allenoate with isatins is presented.