The development of palladium‐catalyzed α‐arylation of carbonyl compounds has emerged as a new avenue in the design of new routes for the synthesis of natural products and active pharmaceutical ingredients (APIs). In many cases, syntheses based on α‐arylation strategies provide elegant routes in terms of increasing the overall yields, improving the synthesis scope, and decreasing the number of steps. This microreview aims to highlight the importance of palladium‐catalyzed α‐arylation methodologies, covering a range of notable reported examples of the total syntheses of structurally important compounds, thereby highlighting the importance of this powerful methodology for key steps in organic synthesis.

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Dedicated to Professor Ibrahim Ibnusaud for his outstanding contributions in the field of organic synthesisDue to the high reactivity of cyclopropanes, different methods have been developed for their stereo-and regio-controlled ring-opening reactions to achieve a variety of synthetically useful targets. The traditional methods for the ring-opening include thermolysis, use of oxidants, transition metals or radical precursors in which many of them encounter various difficulties. In the past several years, visible-light-mediated photoredox reactions received considerable attention for various organic transformations. Several methodologies have been developed in recent times for the visible-light-mediated ring-opening reactions of cyclopropanes. Considering the synthetic potential of this class of reactions, we provide a summary of various methodologies developed for the cyclopropane ring-opening reactions under visible-light photoredox catalysis.

A facile, metal-free method for the synthesis of substituted α-carbolines from secondary Morita–Baylis–Hillman (MBH) acetates of nitroalkenes is presented. The cascade reaction of MBH acetates with tosyliminoindolines occurs regioselectively to form various α-carbolines with a wide substrate scope. The reaction involves mild conditions, and the products are formed in high yields within a short reaction time. The amenability of the reaction to scale up and synthetic applications of the products have been demonstrated.

The reaction of β-ketosulfones with different α-functionalized nitroalkenes affords diversely substituted sulfonylfurans and dihydrofurans. Furthermore, β-ketosulfones react with α-bromonitroalkenes and α-hydrazinonitroalkenes via a cascade Michael addition-cyclization protocol to afford nitrodihydrofurans and hydrazinodihydrofurans, respectively, bearing a key sulfonyl group, in excellent yields with a broad substrate scope. Application of these products has been demonstrated by the synthesis of pyrroles and pyrazoles in good yields. The reaction of β-ketosulfones with nitroallylic acetates yields tetrasubstituted sulfonyl furans through a cascade S N 2′-intramolecular Michael reaction, followed by aromatization. The gram-scale synthesis of a representative example of sulfonylfurans was carried out to demonstrate the synthetic efficiency of the methodology.

As a naturally occurring small-molecule, various optical isomers of chiral pyrrolo[2,1-a]isoquinoline alkaloid crispine A represent a potential class of chiral molecules in contemporary organic chemistry, and possess diverse biological activities. The range of pharmacological activities include antidepressant, antiplatelet, antileukemic, and anticancer activities. This review provides an overview of the literature on the strategies, employed in the synthesis of crispine A in their racemic and enantiopure forms via Bischler-Napieralski cyclization, Pictet-Spengler cyclization, N-Alkylation/Acylation-cyclization, Oxidative cyclization, and Asymmetric hydrogenation in the period of 1931-2021. This study accentuates the need for the developing more effective synthesis, and search for involved biological applications for the pyrroloisoquinoline class of natural product. Attention has been drawn towards the use of relatively less documented but easily accessible naturally occurring diastereomeric scaffolds namely, garcinia and hibiscus acids. These lactones obtained from (+)and (À )-2-hydroxycitric acids bearing chemically amenable functional groups are investigated as an ideal choice for the enantiopure synthesis of the (À )-(R)-and (+)-(S)-Crispine A structural frame work.

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