Recent Progress in Arylmetalative Cyclization/Annulation of Functionalized Alkynes with Organoboranes

Abstract

AbstractAchieving complex molecular assemblies in modular modes is always one of the top priorities of the organic chemist. Cyclization/annulation of functionalized alkynes through carbo metalation has an impactful swath in synthetic organic chemistry. There have recently been considerable contributions in this arena uncovering several new chemical spaces towards new solutions for various fields of biology. On the other hand, organoboronic reagents are fascinating reactive chemprobs, are partake in a broad range of chemical transformations. Particularly utility of these reagents in the carbo‐metalation of alkynes is the subject of high perusal in organic chemistry. To this degree, tuning various transition‐metal catalysts with organoboranes and functionalized alkynes is an intriguing subject for the synthesis of various classes of acyclic and cyclic adducts. Mechanistically, these arylative cyclizations proceed through initial aryl‐metalation on alkynes which provides alkenyl metal species, that concomitantly react with the pendent electrophile. The stereo‐ and regioselective reactivity of this C‐metal is steered by chelation with the coordinating group and/or electrophile on alkyne. In this review, we focused on the critical achievements of the field with the emphasis on the stereoselective capture of the vinyl metal complex with a pendent electrophile. In this field, compilation of the detailed mechanistic pathways in this realm would be helpful to find the gaps and hence to discover novel transformations.