Rhodium catalysed diboration of unstrained internal alkenes and a new and general route to zwitterionic [L2Rh(η6-catBcat)] (cat = 1,2-O2C6H4) complexes†

Dai, Chaoyang; Robins, Edward G.; Yufit, D. S.; Howard, Judith A. K.; Marder, Todd B.; Scott, A. J.; Clegg, William

doi:10.1039/a804710c

Cited by 112 publications

(44 citation statements)

References 4 publications

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“…The diboration of internal alkenes led to the quantitative cis B À B addition to trans-b-methylstyrene and the selective formation of cis-bis(boryl)cyclic moieties for endocyclic alkenes such as indene and norbornene (Figure 3). The diboration of norbornene has been reported using base-free Pt 0 [23] and Rh I complexes, [24] which provided good yields and chemoselectivities but required long reaction times and higher temperatures. Only one report has described the diboration of indene but with lower chemoselectivity (68 %).…”

Section: Methodsmentioning

confidence: 99%

Gold(0) Nanoparticles for Selective Catalytic Diboration

2008

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Section: Methodsmentioning

confidence: 99%

Gold(0) Nanoparticles for Selective Catalytic Diboration

2008

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“…The reaction is significantly slow for disubstituted alkenes and cyclic alkenes, but cyclic alkenes having an internal strain afford the cis-diboration products in high yields (Scheme 9) [35]. A phosphine-gold(I) complex [37] and a zwitter ionic rhodium complex [38] catalyze the diboration of styrene derivatives. Asymmetric diboration of styrene derivatives is demonstrated by using chiral diboron compounds (Scheme 10) [35b].…”

Section: -2 Diboration Of Alkenes 13-dienes and Allenesmentioning

confidence: 99%

Chemistry of Group 13 element-transition metal linkage — the platinum- and palladium-catalyzed reactions of (alkoxo)diborons

Ishiyama

Miyaura

2000

Journal of Organometallic Chemistry

316

117

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The metal-catalyzed borylation of alkenes, alkynes, and organic electrophiles with B-B compounds was developed for the synthesis of and allyl chlorides or acetates was found to yield aryl-, vinyl-, and allylboronates in high yields in the presence of a base and a palladium catalyst, which provides the first one-step procedure for the synthesis of organoboronic esters from organic electrophiles under mild conditions. The mechanisms and the synthetic applications of these reactions are discussed.2

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“…The initial observation in organorhodium chemistry of the catalytic addition of dicatecholdiborane, catalyzed by (optimally) Rh-DPPB, still gave only 44% of the diborated product accompanied by 22% of vinylborane and 22% of "conventional" a-hydroboration product [70]. The work was extended by using the zwitterionic Rh-DPPM complex as the catalyst, where good yields of 1,2-diaddition products were obtained from a range of mono-and disubstituted alkenes [71]. By a relatively minor variation of the reaction conditions, employing RhCl(CO)(PPh 3 ) 2 as the catalyst, either the vinylboronate ester and/or the vinyl bisboronate ester become the main reaction product [72].…”

Section: Catalytic Diboration Of Alkenesmentioning

confidence: 99%

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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Rhodium catalysed diboration of unstrained internal alkenes and a new and general route to zwitterionic [L2Rh(η6-catBcat)] (cat = 1,2-O2C6H4) complexes†

Cited by 112 publications

References 4 publications

Gold(0) Nanoparticles for Selective Catalytic Diboration

Gold(0) Nanoparticles for Selective Catalytic Diboration

Chemistry of Group 13 element-transition metal linkage — the platinum- and palladium-catalyzed reactions of (alkoxo)diborons

Rhodium‐Catalyzed Hydroborations and Related Reactions

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