Asymmetric Suzuki-Miyaura coupling reactions

Figure 13.3 Natural products for which an asymmetric Suzuki-Miyaura coupling reaction has been employed in their syntheses.

Mikami K, Miyamoto T, Hatano M. A highly efficient asymmetric Suzuki-Miyaura coupling reaction catalyzed by cationic chiral palladium(II) complexes. Chem. Commun. 2004 2082-2083. 

Sawai K, Tatumi R, Nakahodo T, Fujihara H (2008) Asymmetric Suzuki-Miyaura coupling reactions catalyzed by chiral palladium nanoparticles at room temperature. Angew Chem Int Ed 47 6917-6919... 

Figure 4.39 Asymmetric Suzuki-Miyaura coupling reactions by using high-molecular-weight polymers as ligands.

A few other chiral NHCP systems have been reported, and their application in various palladium-catalyzed transformations such as hydroamination of a,P-unsaturated nitriles [32], asymmetric Suzuki-Miyaura coupling (see Section 10.2.1) [13n], and most frequently allylic substitution reactions have been studied [29, 33, 34]. Figure 10.3 summarizes the chiral NHCP systems not used in asymmetric hydrogenations, which we will present in the following. 

In this study, the full catalytic cycle for the recently reported asymmetric Suzuki-Miyaura coupling between 1 -bromo-2-methylnaphthalene (2) and 1 -naphthal eneboronic acid (3) catalyzed by a [Pd(bis-hydrazone)] (1) complex [47], was theoretically investigated by means of DFT calculations. Importantly, the results derived from this study revealed that the transmetalation reaction does not occur in just one step, but occurs in three steps. This is owing to the relative lability of the bis-hydrazone ligand, which can easily dissociate one of the N atoms coordinated to the Pd catalyst. Very recently, this variant for the transmetalation mechanism has been reported for the Suzuki-Miyaura coupling catalyzed by a diimine chelated palladium complex [15]. 

Last but not least, theoretical calculations on the investigated asymmetric Suzuki-Miyaura coupling showed that the mechanism for the transmetalation step differs from the typical reaction pathway proposed in the literature. This is owing to the relative lability of the bis-hydrazone ligand, which can easy dissociate one of the N atoms directly coordinated to Pd. As far as the stereochemistry of the reaction is concerned, calculations so far do not provide an explanation for the high enantios-electivities observed in the experiments. Two possible reasons are either the true pathway for the reaction has not been identified yet, or an interconversion among... 

Miyaura, N., Suzuki, A. Paiiadium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chem. Rev. 1995, 95, 2457-2483. Stephenson, G. R. Asymmetric palladium-catalyzed coupling reactions (ed. Stephenson, G. R.) (Chapman Hall, London, 1996) 275-298. Browning, A. F., Greeves, N. Palladium-catalyzed carbon-carbon bond formation (eds. Beller, M.,Bolm, C.) (Wiley-VCH, Weinheim, New York, 1997) 35-64. 

It has been proven that the chiral Pd(II) complexes as transition metal catalysts vs Lewis acid catalysts bring a breakthrough in the frontier of catalytic asymmetric organic synthesis. Here we discussed the key issues based on asymmetric carbon-carbon bond formations anomalous six-membered ring formation, ene-type cyclization leading to five-membered rings, spiro cycliza-tion, alkaloid and quinoline synthesis, Suzuki-Miyaura coupling, and C-H bond activation/C-C bond formation by transition metallic Pd(II) catalysts. On the other hand, the carbonyl-ene reaction, hetero Diels-Alder reaction, and... 

A dichromium derivative has been prepared from pinacol (dichloromethyl)-boronate (163), anhydrous chromous chloride, and lithium iodide in THF at 25 °C [90]. With various aldehydes, RCHO, this reagent adds to the carbonyl carbon to form trans-l-alkenylboronic esters, RCH=CH-B(02C2Me4). For most examples yields were 84-91%, E Z ratios >95 5. This reaction was used recently to convert aldehyde 162 into alkenylboronic ester 164, an intermediate used for a Suzuki-Miyaura coupling in the asymmetric total synthesis of quinine and quinidine (Scheme 8.39) [91]. In the modified procedure, the chromium reagent was generated from 163 in the presence of the aldehyde substrate. 

Scheme 6.2 Asymmetric Suzuki-Miyaura cross-coupling reactions...

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