Asymmetric hydrogenation of 1-phenylethenylboronic acid and esters for the synthesis of chiral organoboron compounds

Ueda, Masato; Saitoh, Atsushi; Miyaura, Norio

doi:10.1016/s0022-328x(01)01239-6

Cited by 32 publications

(19 citation statements)

References 19 publications

(5 reference statements)

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“…These selectivities are comparable to those obtained with the best ligand systems for this substrate class [4 b, c, 190]. Although outperformed by biaryl-based ligands such as BINAP, Me-DuPhos has also shown to be active in the Ru-catalyzed reduction of a-aryl-substituted ethylphosphonates 132 (16-37% ee) [191] and ethanediol 1-phenylethenylboronic ester 133 (42% ee) [192].…”

Section: Enantioselective Hydrogenation Of Miscellaneous C=c Bondsmentioning

confidence: 64%

Enantioselective Hydrogenation: Phospholane Ligands

Cobley¹,

Moran²

2006

The Handbook of Homogeneous Hydrogenation

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The ability to efficiently synthesize enantiomerically enriched materials is of key importance to the pharmaceutical, flavor and fragrance, animal health, agrochemicals, and functional materials industries [1]. An enantiomeric catalytic approach potentially offers a cost-effective and environmentally responsible solution, and the assessment of chiral technologies applied to date shows enantioselective hydrogenation to be one of the most industrially applicable [2]. This is not least due to the ability to systematically modify chiral ligands, within an appropriate catalyst system, to obtain the desired reactivity and selectivity. With respect to this, phosphorus(III)-based ligands have proven to be the most effective.Amongst the hundreds of chiral phosphorus-based ligands developed since the seminal studies of Knowles and Horner [3], only a select few ligand families have had a revolutionary impact on the field. The highly modular chiral C 2 -symmetric phospholane ligands (DuPhos TM and BPE), developed by Burk and coworkers at DuPont, are one such example. As a result, much effort has been directed towards building on this breakthrough discovery and extending both the design and application of this ligand class.In this chapter, we review the growing family of phospholane-based chiral ligands, and specifically examine their applications in the field of enantioselective hydrogenation. In general, this ligand class has found its broadest applicability in the reduction of prochiral olefins and, to a significantly lesser extent, ketones and imines; this is reflected in the composition of the chapter. Several analogous phosphacycle systems have also been included, where appropriate.Whilst trying to be comprehensive, we have also intended to introduce a strong applied flavor to this summary. In the industrial case, catalyst performance is critically judged on overall efficiency, namely catalyst productivity and activity as well as enantioselectivity. As a result, turnover numbers (TONs) and turnover frequencies (TOFs) have been included or calculated whenever possible and meaningful. 773The Handbook of Homogeneous Hydrogenation. Edited by J. G. de Vries and C. J. Elsevier

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Section: Enantioselective Hydrogenation Of Miscellaneous C=c Bondsmentioning

confidence: 64%

Enantioselective Hydrogenation: Phospholane Ligands

Cobley¹,

Moran²

2006

The Handbook of Homogeneous Hydrogenation

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“…This can also be achieved by the hydrogenation of a prostereogenic vinylborane, as was successfully demonstrated by Miyaura and co-workers in 80% enantiomeric excess using a Rh-BINAP complex [45]. In a related approach, the hydrogenation over Pd/C of vinylboronates carrying a remote stereogenic center was shown to exhibit significant levels of diastereocontrol.…”

Section: Diphosphine Ligandsmentioning

confidence: 86%

Rhodium‐Catalyzed Hydroborations and Related Reactions

Brown¹

2005

Modern Rhodium‐Catalyzed Organic Reactions

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The development of metal-catalyzed hydroboration was initiated in a single paper by Männig and Nöth in 1985 [1]. They demonstrated that catecholborane reacted with simple alkenes in the presence of transition-metal catalysts, the most effective being Wilkinson's catalyst, RhCl(PPh 3 ) 3 . Since this reaction of catecholborane with alkenes is normally rather slow, even at elevated temperatures, this observation provided a real opportunity for catalysis. Prior to this work, the only precedent had been the addition of a secondary alkoxyborane to the same rhodium complex, giving a borylrhodium hydride analogous to known silylrhodium hydrides [2]. The synthetic potential of catalytic hydroboration was quickly realized and further extended through Burgess's demonstration of asymmetric catalysis [3], which was later refined and extended by Hayashi [4]. All this early work has been reported in a 1991 review [5], with a later and more extensive review by Belet'skaya and Pelter in 1997 [6]. As these reviews are readily available, the present chapter is confined largely to developments that have taken place since the beginning of 1997. Fig. 2.1 summarizes some of these early milestones. Although metal catalysts other than rhodium have been examined, for example in the palladiumcatalyzed hydroboration of allenes [7], the majority of the interesting developments have been made with rhodium.In the interim period, results have accumulated steadily, in endeavors to address and extend the chemistry beyond the initial perceived limitations. These limitations include the following: (a) the effective catalytic syntheses are confined to the reactions utilizing catecholborane; (b) the scope of alkenes for which efficient rate, regio-and enantioselectivity can be achieved is limited, and (c) the "standard" transformation mandates the oxidation of the initially formed (secondary) boronate ester to a secondary alcohol, albeit with complete retention of configuration [8]. Nonetheless, for noncatalytic hydroboration reactions that lead to the formation of a trialkylborane, a wide range of stereospecific transformations may be carried out directly from the initial product, and thereby facilitate direct C-N and C-C bond formation [9].A reaction pathway for catalytic hydroboration was suggested by Evans and co-workers [10], and amplified through computational studies [11]. This involves the rhodium acting through oxidative addition across the B-H bond, and the resulting borylrhodium hydride complexing to the alkene (reversibly). This is followed by a hydride migration, with a subsequent reductive elimination of the alkylboronate ester to complete 33 2

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“…In 2002, Miyaura and co-workers disclosed the first asymmetric hydrogenation of vinyl boronic esters. [90] Using ar hodium/chiral diphosphine catalyst system under an atmosphere of dihydrogen, 1-phenylethenylboronicesters could be transformed into the corresponding benzylic boronic esters.While the reaction was limited to asingle substrate and ee values of up to only 80 %c ould be achieved, it has since been developed into av aluable method for the synthesis of stereodefined alkyl boronic esters. [91] Morken later developed am ethod with improved enantioselectivity for the hydrogenation of vinyl bis(boronic esters).…”

Section: Asymmetric Transformation Of Prochiral Boron-containing Subsmentioning

confidence: 99%

Asymmetric Synthesis of Secondary and Tertiary Boronic Esters

et al. 2017

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Non-racemic chiral boronic esters are recognised as immensely valuable building blocks in modern organic synthesis. Their stereospecific transformation into a variety of functional groups-from amines and halides to arenes and alkynes-along with their air and moisture stability, has established them as an important target for asymmetric synthesis. Efforts towards the stereoselective synthesis of secondary and tertiary alkyl boronic esters have spanned over five decades and are underpinned by a wealth of reactivity platforms, drawing on the unique and varied reactivity of boron. This Review summarizes strategies for the asymmetric synthesis of alkyl boronic esters, from the seminal hydroboration methods of H. C. Brown to the current state of the art.

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Asymmetric hydrogenation of 1-phenylethenylboronic acid and esters for the synthesis of chiral organoboron compounds

Cited by 32 publications

References 19 publications

Enantioselective Hydrogenation: Phospholane Ligands

Enantioselective Hydrogenation: Phospholane Ligands

Rhodium‐Catalyzed Hydroborations and Related Reactions

Asymmetric Synthesis of Secondary and Tertiary Boronic Esters

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