Shinya Adachi's research while affiliated with University of Toronto and other places

... While the use of 8-methylquinoline N-oxide (2 b) resulted in a lower yield of 3 a (entry 8), those oxidants derived from pyridines, however, were completely ineffective (entries 9 and 10). Other solvents including DCE, PhF, toluene, and THF were less effective or not suitable (entries [11][12][13][14]. ...

Reference:

Reactivities of α‐Oxo BMIDA Gold Carbenes Generated by Gold‐Catalyzed Oxidation of BMIDA‐Terminated Alkynes

... Starting from this consideration and going on with our diversity-oriented synthetic chemistry programs, focused on both IMCRs [16][17][18][19][20][21][22][23][24] and boron-containing compounds [25,26], we considered aliphatic isocyano boronic acids as attractive components, able to greatly increase IMCRs products scope, as better well-known boryl aldehydes [27,28] and amino boronic acids [29] already do. Boron-containing peptidomimetics are currently highly relevant in drug discovery, mainly due to the ability of amino boronic acids to act as amino acid bioisosteres and reversible covalent inhibitors [30]. Their demonstrated mechanisms of interaction with nucleophilic groups in biomolecules underlie the use of such compounds in medicinal chemistry, resulting in many boron-containing drugs approved by FDA in the last few years [31]. ...

Reference:

Enantiopure β-isocyano-boronic esters: synthesis and exploitation in isocyanide-based multicomponent reactions

... To the best of our knowledge, similar studies have been reported so far only on amidation using BnNH 2 by the Dewynter group (Scheme 1d) 14 and ring expansion by the Yudin group (Scheme 1e). 15 Although the two groups have conducted pioneering studies on metal-free C-N bond cleavage of lactams, reactions such as intermolecular peptide bond formation have not yet been examined, and there is signicant scope for improvement in terms of substrate limitation and versatility. ...

Reference:

An economical approach for peptide synthesis via regioselective C–N bond cleavage of lactams

... Nitrogen-containing aromatic heterocyclic compounds, particularly imidazoles, have garnered significant attention in research and industrial chemistry in recent years, mainly due to their versatile range of biological and pharmacological activities [1]. They play a pivotal role in the synthesis of biologically active molecules [2,3], such as anticancer, antiaging, anticoagulant, anti-inflammatory, antimicrobial, antitubercular, antidiabetic, antimalarial, antiviral drugs, and enzyme inhibitors [4][5][6]. ...

Reference:

Synthesis of imidazole derivatives in the last 5 years: An update

... As depicted in Scheme 1, one of the classic approaches to synthesize 1,2,4,5-tetrasubstituted or 2,4,5-trisubstituted imidazoles is the three-component cyclization of α-diketone, aldehyde, and amine or ammonia sources catalyzed by transition metal complexes or under acidic conditions (Equation (1)). Recently, this protocol has been evolved using internal alkynes as starting materials via generating 1,2-diketones in situ by oxidation reaction [21][22][23][24]. On the other hand, the formal [3+2] annulation of substituted amidines with alkyne forming imidazole ring usually shows high atom-utilization, and two representative procedures are concluded in Scheme 1. ...

Reference:

Base-Promoted Annulation of Amidoximes with Alkynes: Simple Access to 2,4-Disubstituted Imidazoles

... We surmised that borylated b-ketoesters could be synthesized through a Lewis acid-catalyzed Roskamp reaction. [7] Our investigation focused on parent acyl-MIDA boronate 1 a, as it is easily accessible, [8] and commercially available ethyl diazoacetate 2 as reaction partners. The presence of a Lewis acid was necessary for the reaction to occur (Table 1, entry 1). ...

Reference:

A Boron Scan of Ethyl Acetoacetate Leads to Versatile Building Blocks

... Although many synthetic methods are now available for amino boronic acids derivatives, their application for preparation of peptidomimetics and heteroatom-rich boron-containing small molecules remains underdeveloped. [8,9] Remarkable exceptions come from the impressive work of Professor Yudin and his research group, which, over the last few years, exploited various borylated reagents [10,11] and, in particular, both αand βamino boronic acids, [12][13][14] even coming to the discovery of boron-based peptidomimetics endowed with relevant biolog-ical activities. [7,[15][16] Quite recently, from the same group, amidoboronic acid-containing peptidomimetics with constrained backbone were also achieved, and successfully demonstrated as novel VIM-2 metallo-β-lactamase inhibitors [17] (Figure 1). ...

Reference:

Exploiting Enantiopure β‐Amino Boronic Acids in Isocyanide‐Based Multicomponent Reactions

... [22] Considering the stability of acylborons, we decided to include the well-known MIDA boronate (MIDA = methyliminodiacetic acid) into the structure of CABT. Following Yudin's α-bromoacetyl boronate synthesis, [23] ring-opening chlorination of commercially available BMIDA-ethylene oxide produced chlorohydrin 2. This chlorohydrin was then oxidized by Dess-Martin periodinane to form acylboron 3. Finally, the reaction of 3 with tosylhydrazide produced the desired CABT in a good yield. Of note, this procedure is highly reproducible and scalable, and does not require any silica-gel column purification. ...

Reference:

Chloroacetyl boronate N-tosylhydrazone as a versatile synthetic building block

... [8,9] Remarkable exceptions come from the impressive work of Professor Yudin and his research group, which, over the last few years, exploited various borylated reagents [10,11] and, in particular, both αand βamino boronic acids, [12][13][14] even coming to the discovery of boron-based peptidomimetics endowed with relevant biolog-ical activities. [7,[15][16] Quite recently, from the same group, amidoboronic acid-containing peptidomimetics with constrained backbone were also achieved, and successfully demonstrated as novel VIM-2 metallo-β-lactamase inhibitors [17] (Figure 1). ...

Reference:

Exploiting Enantiopure β‐Amino Boronic Acids in Isocyanide‐Based Multicomponent Reactions

... [40] Our work on a-boryl enamine functionalization led us to consider electrophilic fluorination chemistry towards fluorinated b-aminoalkylboronic acids. [41][42][43] We subjected N-methyliminodiacetic acid (MIDA)-protected a-boryl acetaldehyde [44] 1 to electrophilic fluorination employing Selectfluor or N-fluorobenzenesulfonimide (NFSI) and catalytic amounts of pyrrolidine. Initial screening showed modest conversion with poor selectivity (Table 1, Entries 1-6). ...

Reference:

Synthesis of Fluorinated Aminoalkylboronic Acids from Amphoteric α‐Boryl Aldehydes