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Photoinduced borylation is becoming a fascinating and growing research field in synthetic chemistry. On the other hand, electron donor–acceptor (EDA) complex photoactivation has emerged as an alternative strategy to generate active open‐shell species without the need for photosensitizers. Suitable organoboron compounds can serve as the electron donor or acceptor to form the corresponding electron donor–acceptor complexes, which then undergo photoinduced intracomplex single electron transfer (SET) to generate carbon‐ or boron‐centered radicals for the construction of new C−B bonds. In this Concept paper, we review recent advances in photoinduced borylation via the EDA complex photoactivation strategy surveying the relevant literature until December 2022. [ABSTRACT FROM AUTHOR]

We report the design of a bifunctional metal–organic layer (MOL), Hf12‐Ru‐Co, composed of [Ru(DBB)(bpy)2]2+ [DBB‐Ru, DBB=4,4′‐di(4‐benzoato)‐2,2′‐bipyridine; bpy=2,2′‐bipyridine] connecting ligand as a photosensitizer and Co(dmgH)2(PPA)Cl (PPA‐Co, dmgH=dimethylglyoxime; PPA=4‐pyridinepropionic acid) on the Hf12 secondary building unit (SBU) as a hydrogen‐transfer catalyst. Hf12‐Ru‐Co efficiently catalyzed acceptorless dehydrogenation of indolines and tetrahydroquinolines to afford indoles and quinolones. We extended this strategy to prepare Hf12‐Ru‐Co‐OTf MOL with a [Ru(DBB)(bpy)2]2+ photosensitizer and Hf12 SBU capped with triflate as strong Lewis acids and PPA‐Co as a hydrogen transfer catalyst. With three synergistic active sites, Hf12‐Ru‐Co‐OTf competently catalyzed dehydrogenative tandem transformations of indolines with alkenes or aldehydes to afford 3‐alkylindoles and bisindolylmethanes with turnover numbers of up to 500 and 460, respectively, illustrating the potential use of MOLs in constructing novel multifunctional heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

A Pd‐catalyzed three‐component carbonylative‐annulation of 1‐hydroxy‐o‐carborane, internal alkyne and carbon monoxide has been achieved via direct and regioselective cage B−H activation. A class of C,B‐substituted carborano‐coumarin derivatives with potential applications in pharmaceuticals were facilely prepared in moderate to high yields with excellent chemoselectivity and regioselectivity. A plausible reaction mechanism including CO insertion, electrophilic B−H metalation, alkyne insertion and reductive elimination was proposed. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: Ir‐catalyzed cascade dehydrogenative CH/BH and BH/OH cross‐coupling of carboranyl carboxylic acid with readily available benzoic acid has been achieved, leading to the facile synthesis of previously unavailable carborano‐coumarin in a simple one‐pot process. Two cage B—H, one aryl C—H and one O—H bonds are activated to construct efficiently new B—C and B—O bonds. The cascade cyclization can stop at the first B—H/C—H cross‐coupling step by tuning the reaction conditions, resulting in a series of α‐carboranyl benzoic acid and aryl carborane derivatives. Control experiments indicate that B—H/C—H dehydrocoupling proceeds preferentially over B—H/O—H dehydrocoupling, and both directing groups and oxidants are crucial for this reaction. An iridium(V) intermediate is proposed to be involved in the catalytic cycle. [ABSTRACT FROM AUTHOR]

Abstract: Carboranes are a class of carbon–boron molecular clusters with unusual thermal and chemical stabilities. They have been proved as very useful building blocks in supramolecular design, optoelectronics, nanomaterials, boron neutron capture therapy agents and organometallic/coordination chemistry. Thus, the functionalization of o‐carboranes has received growing interests. Over the past decades, most of the works in this area have been focused on cage carbon functionalization as the weakly acidic cage C−H proton can be readily deprotonated by strong bases. In sharp contrast, selective cage B−H activation/functionalization among chemically very similar ten B−H vertices is very challenging. Considering the differences in electron density of ten cage B−H bonds in o‐carborane and the nature of transition metal complexes, we have tackled this selectivity issue by means of organometallic chemistry. Our strategy is as follows: using electron‐rich transition metal catalysts for the functionalization of the most electron‐deficient B(3,6)−H vertices (bonded to both cage CH vertices); using electron‐deficient transition‐metal catalysts for the functionalization of relatively electron‐rich B(8,9,10,12)−H vertices (with no bonding to both cage CH vertices); and using the combination of directing groups and electrophilic transition metal catalysts for the functionalization of B(4,5,7,11)−H vertices (bonded to only one cage CH vertex). Successful applications of such a strategy result in the preparation of a large variety of cage B‐functionalized carboranes in a regioselective and catalytic manner, which are inaccessible by other means. It is believed that as this field progresses, other cage B‐functionalized carboranes are expected to be synthesized, and the results detailed in this concept article will further these efforts. [ABSTRACT FROM AUTHOR]

The article mentions selective fluorination of ortho-carboranes catalyzed by palladium, published in the volume 135 of 2013 issue of the "Journal of the American Chemical Society."