Boronic Esters in Asymmetric Synthesis

Matteson, Donald S.

doi:10.1021/jo4013942

Cited by 267 publications

(128 citation statements)

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“…The transformation involves the stereoretentive complexation of the lithiated carbamate 12 /TIB ester 13 with the boronic ester to form a boronate complex, which then undergoes a stereoinvertive 1,2-metallate rearrangement 14 to generate a homologated boronic ester. Our attention was drawn to commercially available diborylmethane 1 , 15 which we envisioned serving as a valuable reagent for the elaboration of stereodefined carbenoids (Fig.…”

Section: Introductionmentioning

confidence: 99%

Selective uni- and bidirectional homologation of diborylmethane

et al. 2017

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Section: Introductionmentioning

confidence: 99%

Selective uni- and bidirectional homologation of diborylmethane

et al. 2017

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“…Nevertheless, the desire of industry to reduce its reliance on the use of precious metals in coupling reactions and the need for very low metal levels in active pharmaceutical ingredients has increased interest in metal-free coupling processes considerably. 14 Boronic esters 15 and acids 16 are considered to be important coupling partners as they are versatile intermediates for the preparation of a wide variety of molecules. For example, Barluenga 17 and others [18][19][20] recently demonstrated the powerful application of a reductive metal-free cross-coupling between tosylhydrazones and boronic acids.…”

Section: Introductionmentioning

confidence: 99%

Iterative reactions of transient boronic acids enable sequential C–C bond formation

et al. 2016

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(2016). Iterative reactions of transient boronic acids enable sequential C-C bond formation. Nature Chemistry, 8 (4), 360-363. Copyright and re-use policySee http://shura.shu.ac.uk/information.html Sheffield Hallam University Research Archivehttp://shura.shu.ac.uk The ability to form multiple carbon-carbon bonds in a controlled sequence and thus rapidly build molecular complexity in an iterative fashion is an important goal in modern chemical synthesis. In recent times, transition metal-catalysed coupling reactions have dominated in the development of C-C bond forming processes. A desire to reduce the reliance on precious metals and a need to obtain products with very low levels of metal impurities has brought a renewed focus on metal-free coupling processes. Here, we report the in situ preparation of reactive allylic and benzylic boronic acids, obtained by reacting flow-generated diazo compounds with boronic acids, and their application in controlled iterative C-C bond forming reactions is described. Thus far we have shown the formation of up to three C-C bonds in a sequence including the final trapping of a reactive boronic acid species with an aldehyde to generate a range of new chemical structures. Iterative reactions of transient boronic acids enable sequential C-C bond formation IntroductionThe generation of C-C bonds is at the heart of synthetic organic chemistry. 1 The ability to form multiple C-C bonds using iterative or one-pot methods allows a rapid increase in molecular complexity.2-5 While many such sequences are known, there is still room to exploit new reactivity patterns and different chemical combinations derived from reactive intermediates. 6 In recent times, transition metal chemistry has dominated C-C bond cross-coupling strategies. [7][8][9][10][11][12][13] This powerful approach has been central to the planning and execution of modern synthesis programs both in academia and industry. Nevertheless, the desire of industry to reduce its reliance on the use of precious metals in coupling reactions and the need for very low metal levels in active pharmaceutical ingredients has increased interest in metal-free coupling processes considerably. 14 Boronic esters 15 and acids 16 are considered to be important coupling partners as they are versatile intermediates for the preparation of a wide variety of molecules. For example, Barluenga 17 and others [18][19][20] recently demonstrated the powerful application of a reductive metal-free cross-coupling between tosylhydrazones and boronic acids. The reaction likely proceeds via a carbene-like species which on combination with a boronic acid initiates a sequence of reactions that terminates in the formation of a coupling product. However, high temperatures are necessary to affect these coupling processes so that any further exploitation of potentially useful intermediates in the reaction has not been possible so far.From our own mechanistic studies based on the use of flow-generated diazo compounds, 21 in the metal-free cross-coupling with aryl boronic a...

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“…The fundamental work on the asymmetric homologation of organoborons was carried out by Matteson in the 1980s [3][4][5]. In his contributions, a chiral auxiliary was embedded in the diol unit of the boronic ester, and a two-step sequence, consisting of the (1) addition of chloromethyl lithium and (2) addition of an achiral Grignard, was employed.…”

Section: Introductionmentioning

confidence: 99%