Asian Journal of Organic Chemistry最新文献

The direct ortho‐alkynylation of substituted phenylalanine has been successfully achieved through methoxyiminoacyl (MIA)‐mediated Pd‐catalyzed C−H functionalization. This innovative protocol showcases the ability to apply a diverse range of phenylalanine substrates, resulting in the efficient synthesis of alkynylation benzylamine derivatives with notable effectiveness. Computational investigations further revealed that the fluoride ion enhances the electropositivity of Pd(IV) and the interaction between C1 and C2 within the transition state of the reductive elimination, which significantly expedites the reductive elimination step in the alkynylation process.

The excellent reactivity of diaryliodonium salts has primarily been attributed to the efficient departure of the iodoarene unit, facilitating a variety of arylation reactions. However, one equivalent of iodoarene as a side‐product is a chemical waste in these reactions, which was criticized by chemists for hindering its popularity. Recently, the development of synthetic methodology that preserve the aryl iodine moiety received increasing attention. Oxidative rearrangement reactions involving aryliodonium reagents have significantly addressed the atom‐economic issue, thereby broadening the reaction scope. The resulting intricate aryliodine products are viewed as valuable synthons for the synthesis of natural products, pharmaceutical intermediates and other fine chemicals.

2‐Arylsulfonyl‐2‐azabicyclo[2.2.1]hept‐5‐enes, synthesized via the cycloaddition of chloral‐ or dichloro(phenyl)acetaldehyde N‐arylsulfonylimines to cyclopentadiene, undergo Wagner‐Meerwein rearrangement under the action of bromine or chlorine to afford 3‐polychloro‐6,7‐dyhalogenated 2‐arylsulfonylazabicyclo[2.2.1]heptanes.

A convenient route for the preparation of tetrahydropyran (THP) derivatives with a quaternary and tertiary vicinal stereocenters is reported. The atom economy acid‐catalyzed cyclization of allylsilyl alcohols provided polysubstituted tetrahydropyrans in good yields and excellent diastereoselectivities (>95 : 5). In comparison with the traditional oxymercuration procedure, this approach resulted to be more efficient in both yield and stereocontrol.

Palladium‐catalyzed carbonylation of aryl sulfonium salts with CO₂ as a CO surrogate has been successfully developed via a one‐pot two‐step procedure. Thus, by merging thianthrenation and the carbonylation, site‐selective aromatic C−H carbonylation of a plethora of readily available arenes can be realized with CO₂, providing access to a variety of structurally diverse and useful benzamides, esters and carboxylic acids. Simple operation, broad substrate scope, good functional group tolerance and mild reaction conditions are the attractive features of the method. Late‐stage functionalization of complex bioactive molecules as well as the precise synthesis of pharmaceuticals 1‐BCP and butoxycaine demonstrated the potential application of the established protocol.

A procedure utilizing [TBA][P(SiCl₃)₂] as P source for the synthesis of phosphinecarboxamides is presented. The synthesis involves the reaction of [TBA][P(SiCl₃)₂] with isocyanates. These compounds act as highly effective reagents for the subsequent phosphination of isocyanates, leading to the formation of phosphine(triscarboxamides). This reaction proceeds swiftly under mild and straightforward conditions, making it suitable for a wide range of commercially available isocyanates.

A general and convenient selective direct arylation of the 3‐position of triimidazo[1,2‐a:1’,2’‐c:1’’,2’’‐e][1,3,5]triazine (1) with (hetero)aryl halides in DMA was successfully achieved in the presence of K₂CO₃ as the base and a catalyst precursor consisting of Pd(OAc)₂ and P(2‐furyl)₃. Electron‐poor and ‐rich (hetero)aryl moieties, including the strongly deactivated and sterically encumbered 2,4,6‐trimethoxyphenyl unit, are well tolerated in the electrophilic partner. The data obtained in this synthetic study support a reaction mechanism involving an electrophilic attack of an arylpalladium‐(II) halide species onto the triazine ring.

Attempts to carry out intramolecular annulation of 9,10‐diarylbenzo[h]quinolines and 9,10‐di(hetero)arylphenanthrenes to aromatics with expanded π‐conjugated systems by using different methods are described. The starting compounds (9,10‐diarylbenzo[h]quinolines and 9,10‐di(hetero)arylphenanthrenes) were prepared by C−C bond activation in 1‐azabiphenylene or biphenylene followed by insertion of internal alkynes. Interestingly, unlike in purely carbon‐based aromatics, the course of the annulation turned out to be highly dependent on the structure of maternal compounds. In a handful of cases were obtained the expected or desired products. In others, unexpected rearrangements of the basic molecular frameworks were observed.

The total syntheses of eutyscoparol A and violaceoid C via violaceoid A, have been accomplished including the improved total syntheses of violaceoid A and violaceoid B. This synthetic method, which employed the desymmetrization of a symmetric diol, enabled divergent access to other violaceoids, eutyscoparols, and their derivatives.

The development of a low‐cost, reusable, and sustainable approach is a difficult and emerging demand in the coming arena. Here, we demonstrate the selective oxidation of primary alcohol, styrene to aldehyde, and alkyl benzene to appropriate ketone, under Blue LED irradiation. The developed approaches employ reusable catalysts (V₂O₅/TIO₂) and green solvents (ACN, H₂O) at room temperature. The substrate scope is widely investigated for various compounds of different functionalities. Organic transformations are supported by reaction mechanistic studies. The gram scale reaction and catalytic recyclability were also carried out to maximize the protocol's synthetic utility.