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.

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.

A facile, base-and catalyst-free synthesis of Morita−Baylis−Hillman and Rauhut−Currier adducts of βaminonitroalkenes with different electrophiles such as ethyl glyoxylate, trifluoropyruvate, ninhydrin, vinyl sulfone, and Ntosylazadiene is reported. The products are formed in good to excellent yields at room temperature with a broad substrate scope. The adducts of ninhydrin and β-aminonitroalkene spontaneously cyclize to fused indenopyrroles. Gram-scale reactions and synthetic transformations of the adducts are also reported here.

The Cover Feature shows naturally occurring (2S,3S)‐ and (2S,3R)‐tetrahydro‐3‐hydroxy‐5‐oxo‐2,3‐furan dicarboxylic acid bearing, chemically amenable functional groups that are an ideal choice for the enantiopure synthesis of the (−)‐ and (+)‐Crispine A, respectively. The diastereomeric natural products are conveniently converted to desirable enantiomers of Crispine A through the chiral pool strategy. This exciting and efficient strategy is one of the well‐explored trends in synthetic organic chemistry, especially regarding molecules procured from tropical plant material (Nature) and serves as key step in the enantiopure synthesis of small‐molecule natural products. More information can be found in the Minireview by C. Mohan, I. Ibnusaud et al.

Arynes are a privileged class of reactive intermediates in synthetic organic chemistry, and their unusual reactivities have been the subject of engrossing research interest. Recently, arynes-based synthetic innovations have been...