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1,1-Diborylalkene, a class of important diboryl species, serves as the synthetic precursor of multisubstituted olefin, which is a prevalent building block in natural products, functional materials, and pharmaceuticals. Current methods mainly afford symmetrical 1,1-diborylalkenes, and late-stage differentiation of the two identical boryl groups is required to achieve selective difunctionalization. In comparison, stereoselective synthesis of unsymmetrical 1,1-diborylalkenes (UDBA) are less-explored. This Synpacts article provides a brief summary of the achievements in the synthesis of UDBAs. In particularly, we highlight our recent work on the unsymmetrical 1,1-diborylation of alkynes using a neutral sp2 sp3 diboron reagent to access UDBAs and their controllable stepwise derivatization. 1 Introduction 2 Background: Unsymmetrical 1,1-Diborylalkene Synthesis 3 Stereoselective Unsymmetrical 1,1-Diborylation of Alkynes with a Neutral sp2 sp3 Diboron Reagent 4 Summary and Outlook.

The incorporation of two distinct boryl groups at the same carbon center in organic molecules has attracted growing research interest due to its potential for facilitating controlled, precise synthesis through stepwise dual carbon-boron bond transformations. Here we report a method to access unsymmetrical 1,1-diborylalkene (UDBA) stereoselectively via the reaction of readily available alkynes with a neutral sp2−sp3 diboron reagent (NHC)BH2-Bpin (NHC=N-heterocyclic carbene). Attributing to the chemically easily distinguishable nature of the sp2 and sp3 boryl moieties, controllable stepwise derivatization of the resultant UDBAs is realized. This process leads to various multifunctionalized olefins and organoborons, such as acylboranes, which are difficult to prepare by other methods. © 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

Meng Zhang,1,* Wenyi Lu,2,* Danni Xie,1 Jiaxi Wang,1 Xia Xiao,2 Yedi Pu,2 Juanxia Meng,2 Hairong Lyu,2 Mingfeng Zhao2 1First Center Clinic College of Tianjin Medical University, Tianjin, 300192, People’s Republic of China; 2Department of Hematology, Tianjin First Central Hospital, Tianjin, 300192, People’s Republic of China*These authors contributed equally to this workCorrespondence: Mingfeng Zhao; Hairong Lyu, Department of Hematology, Tianjin First Central Hospital, Tianjin, 300192, People’s Republic of China, Email mingfengzhao@sina.com; 18802235939@163.comBackground: Metagenomic next-generation sequencing (mNGS) is a fast, sensitive and accurate diagnostic method for pathogens detection. However, reports on the application of mNGS in mucormycosis remain scarce.Methods: From January 2019 to December 2021, we recruited 13 patients with hematological malignancies who were suspected of mucormycosis and completed mNGS in D20. Then we retrospectively analyze the clinical data, diagnosis, therapeutic process, and outcomes. In order to evaluate the diagnostic value of mNGS in hematological malignancies patients with suspected mucormycosis.Results: All patients had high risk factors of Invasive Fungal Disease, including hematopoietic stem cell transplantation, immunosuppression, glucocorticoids, etc. The clinical presentations were pulmonary (n=9), rhino-orbito-cerebral (n=4). But the manifestations were nonspecific. All enrolled patients completed mNGS. And most (8/13, 61.54%) of the samples were from blood. Fungi can be detected in all specimens, including Rhizopus (n=7), Rhizomucor (n=4) and Mucor (n=2). In addition, 7/13 (53.85%) specimens were detected bacteria at the same time and virus were detected in 5/13 (38.46%). Histopathological examination was completed in 5 patients, 3 of which were completely consistent with the results of mNGS. After treatment, 6 patients were cured, while the other 7 patients died.Conclusion: mNGS may be a

We disclose herein the first example of iron-catalyzed regioselective intramolecular C–H/B–H dehydrogenative coupling, affording unprecedented C,B-substituted carborane-fused phenanthroline derivatives. The 8-aminoquinoline type auxiliaries not only serve as the bidentate directing groups but also ingeniously become the core part of the final products. The mechanistic hypothesis includes B–H activation, directing group rotation promoted by trans effect, C–H activation, and reductive elimination.

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.

Copper-catalyzed electrochemical selective cage B–H oxygenation of o-carboranes has been achieved for the first time. Under a constant electric current (4.0 mA) at room temperature, copper-catalyzed cross-coupling of carboranyl amides with lithium phenolates results in the formation of B(4,5)-diphenolated o-carboranes via direct B–H activation, whereas the use of lithium tert-butoxide affords B(4)-monooxygenated products. This reaction does not require any additional chemical oxidants and generates H2 and a lithium salt as byproducts. Control experiments indicated that a high-valent Cu(III) species is likely involved in the reaction process.

A proof-of-principle study of cascade dehydrogenative cross-coupling of carboranyl carboxylic acid with readily available benzamide has been achieved, resulting in the facile synthesis of previously inaccessible carborano-isoquinolinone derivatives in a simple one-pot process, in which two cage B–H, one aryl C–H, and one N–H bond were sequentially activated to construct efficiently new B–C and B–N bonds, respectively. Under suitable reaction conditions, such cascade cyclization can be stopped at the first B–H/C–H cross-coupling step to give a series of α-carboranyl benzamides, suggesting the preferential occurrence of B–C cross-coupling over that of B–N. The carboxylic acid directing group plays a key role in the B–C cross-coupling step, which is then removed through in situ decarboxylation. The CV results combined with control experiments indicate that high-valent Ir(V)-species may be involved in the reaction pathways, which is crucial for such cascade dehydrogenative cross-coupling reactions. The isolation and structural identification of a key intermediate, its controlled transformations, and deuterium labeling experiments support a new Ir-nitrene-mediated amination for B–H/N–H dehydrocoupling.

A proof-of-concept example of catalytic regioselective cage B(8)–H functionalization of o-carboranes has been disclosed for the first time. Under the help of an acylamino directing group at cage B(3), a series of B(8)-arylated, B(4,7,8)-triarylated and B(4,7,8)-trifluorinated o-carborane derivatives were conveniently prepared. On the basis of isolation of a key intermediate, deuterium labeling experiments and DFT calculations, a reaction mechanism involving a high-valent palladium induced “cage-walking” from B(4) to B(8) vertex is proposed to account for the regioselective B(8)–H activation.

A one-pot strategy for efficient and facile synthesis of C,B-substituted carborane-fused N-polyheterocycles is reported. A rhodium catalyzed cascade cyclization of carboranyl N-arylimines with vinyl ketones enables the effective construction of three new B–C and C–C bonds in one reaction. Both carboranyl B–H and aryl C–H bonds are sequentially activated, leading to a series of previously unavailable C,B-substituted carborane-fused cyclopenta[b]quinoline derivatives, for potential applications in pharmaceuticals and materials, in a step-economical manner. The successful isolation and structural identification of a key intermediate provide solid evidence for the reaction mechanism, involving a tandem sequence of regioselective B–H activation, alkene insertion, nucleophilic cyclization, C–H activation, nucleophilic cyclization, dehydration and oxidative aromatization.

Ir-Catalyzed –COOH directed site-selective B–H/C–H dehydrogenative cross-coupling of o-carborane with thiophenes has been achieved for the first time. Without any pre-functionalization, carboranyl carboxylic acids and thiophenes can serve as suitable coupling partners, resulting in the preparation of 4-thienyl-o-carboranes in a simple one-pot process for potential applications in materials.

Transition metal catalyzed, regioselective carborane-cage B(4)−H iodination, bromination, and chlorination as well as B(4,5)−H diiodination were achieved by using NXS (X=I, Br), FeCl3, or IOAc as the halogenating agent, respectively. A series of previously inaccessible B(4)-halogenated o-carboranes were synthesized in a simple one-pot process, and proved to be valuable synthons for the functionalization of carboranes. Mono- and di-selectivity can be controlled by in situ removal of the carboxy directing group. The resultant 4-I-o-C2B10H11 can serve as a versatile feedstock for the construction of cage B−C(sp2), B−C(sp), B−O, and B−N bonds.

A rhodium-catalyzed hydroxylation of a cage B4−H bond in o-carboranes with either O2 or air as the oxygen source is described, and serves as a new methodology for the regioselective generation of a series of 4-OH-o-carboranes in a one-pot process. The use of either O2 or air as both the oxidant and the oxygen source makes this protocol very environmentally friendly and practical.

Transition metal catalyzed regioselective amination of the cage B(4)–H bond in o-carboranes has been achieved for the first time using O-benzoyl hydroxylamines or organic azides as the amination reagents, leading to the preparation of a series of tertiary and secondary carboranyl amines. Both amination reactions proceeded under mild conditions without the addition of any external oxidants. Hydrogenolysis of the resultant product 4-N(CH2Ph)2-o-carborane afforded the primary carboranyl amine, 4-amino-o-carborane, in quantitative yield.

Palladium-catalyzed direct dialkenylation of cage B(4,5)H bonds in o-carboranes has been achieved with the help of a carboxylic acid directing group, leading to the preparation of a series of 4,5-[trans-(ArCHCH)]2-ocarboranes in high yields with excellent regioselectivity. The traceless directing group, eliminated during the course of the reaction, is responsible for controlling regioselectivity and dialkenylation. A possible catalytic cycle is proposed, involving a tandem sequence of PdII-initiated cage BH activation, alkene insertion, β-H elimination, reductive elimination, and decarboxylation.