Suzuki intramolecular

Brick et al. have studied this bromination in more detail and showed that the extent of the bromination can be controlled by changing the ratio of the reagents. The first substitution was found to be in the para position but subsequent intramolecular rearrangements allowed the formation of 2-5-dibrominated species. Brick et al. also reported the functionalization of such species using Pd-catalyzed reactions such as Heck and Suzuki couplings to give fully substituted p-stilbenes, p-biphenyls, diarylamines, and methylcinnamates. Hydrogenation of... 

Attempted intermolecular cross-benzoin reactions typically generate a thermodynamically controlled mixture of products [50], although several groups including Enders [51], Suzuki [52] and You [53] have utilised catalysts 116-118 for the intramolecular crossed benzoin of keto-aldehydes (Scheme 12.22). 

Suzuki and co-workers recently applied the asymmetric intramolecular benzoin reaction to the synthesis of the homoisoflavonoid (-F)-sappanone B 122 [54]. The authors found that triazolium salt pre-catalyst 120 gave the best results for the... 

Intramolecular Suzuki reactions have been done by hydroboration followed by... 

For the domino transition metal-catalyzed synthesis of macrocycles, conditions must be found for two distinct cross-coupling reactions, of which one is inter- and the other intramolecular. For this purpose, Zhu s group [115] has developed a process of a Miyura arylboronic ester formation followed by an intramolecular Suzuki reaction to give model compounds of the biphenomycin structure 6/1-232 containing an endo-aryl-aryl bond. 

An intramolecular Pd-catalyzed ring closure of an allylic halide, acetate or carbonate containing an allene moiety as 6/1-256, followed by a Suzuki reaction, was used by Zhang and coworkers for the synthesis of five-membered carbo- and heterocycles 6/1-257 and 6/1-258 (Scheme 6/1.67) [125]. 

Another Suzuki coupling reaction was described by Zhang et al., to produce arylindoles 116a and b, using solid-phase synthesis [76]. The synthesis was achieved by palladium-mediated coupling/intramolecular indole cycli-zation of resin-bound 2-trimethylsilylindole 117, Scheme 29. 

K. Hamasaki, H. Ikeda, A. Nakamura, A. Ueno, F. Toda, I. Suzuki, andT. Osa, Fluorescence sensors of molecular recognition. Modified cyclodextrins capable of exhibiting guest-responsive twisted intramolecular charge transfer fluorescence, /. Am. Chem. Soc. 775,5035-5040(1993). 

The dimerization of aldehydes to form esters is a completely atom-efficient process known as the Tishchenko reaction, which involves no net oxidation or reduction. Suzuki, Katoh, and coworkers have used complex 77 to catalyze the Tishchenko reaction of a range of aldehydes, including dihydrocinnamaldehyde 91 and benzaldehyde 14 (Scheme 22) [81]. The same catalyst has been used for an intramolecular variant of the reaction, where keto-aldehyde 92 isomerizes to lactone 93 via an intramolecular Tishchenko reaction. The oxidized product is formed as a by-product,... 

Suzuki and co-workers reported the intramolecular cross-benzoin reaction utilizing thiazolium pre-catalyst 35 to obtain products such as 37 and 38 (Eq. 3) [49],... 

Table 4 Suzuki and co-workers enantioselective intramolecular cross-benzoin]...

Similarly, while exploring a route toward the synthesis of strychnine, Bodwell and Li reported hydroboration of i f-[2-(l-allyl-17/-indol-3-yl)ethyl]-6-iodopyridazin-3-amine 184 followed by intramolecular Suzuki reaction (Scheme 45) <2002AGE3261>. 

Ruhland et al. used PdCl2(dppf)-NEt3 Heck conditions to add to a resin-bound aryl iodide, thereby generating supported 4-styryl (3-lactams, as shown in Scheme 17.45 This catalyst system, also found to be effective for the Suzuki reaction (see Section 2.4), is unusual for the Heck reaction and had only previously been used for an intramolecular cyclization.46 The more usual conditions of Pd(OAc)2/phosphine/NEt3 or K2C03 were found to be ineffective. 

Asymmetric induction of central chirality at a carbon atom was achieved by an intramolecular enantioposition-selective asymmetric cross-coupling [12]. Treatment of the prochiral bisbo-rane 46, which was prepared from the alkenyl triflate 45 and 2 equiv. of 9-BBN with 20 mol % of Pd/(S)-(/ )-BPPFOAc (48) catalyst generated in situ in THF, brings about intramolecular Suzuki coupling. The following oxidative workup and p-nitrobcnzoylation affords the chiral cyclopentane derivative (R)-47 in 58% yield and 28% ee (Scheme 8F.14). 

Jia Y, Bois-Choussy M, Zhu J (2008) Synthesis of Diastereomers of Complestatin and Chloropeptin I Substrate-Dependent Atropstereoselectivity of the Intramolecular Suzuki-Miyaura Reaction. Angew Chem Int Ed 47 4167... 

In order to introduce functionality at key positions, an intramolecular Diels-Alder reaction with furan as the diene component was planned. Suzuki coupling of the previously mentioned 105 with furan-3-boronic acid 106 gave compound 107, which was N-tosylated to 108. Construction of the dienophile portion was performed as in the previous case, by addition of vinylmagne-sium bromide to give 109, followed by MnC>2 oxidation to give the cyclization precursor, which was immediately heated at 120 °C in toluene and afforded compound 110, which incorporates an oxygen atom at both the ketone and vinyl chloride positions of welwistatin (Scheme 24). 

As an obvious extension of the benzoin reaction, the cross-coupling of aldehydes or of aldehydes and ketones was first achieved with the thiamine-dependent enzyme benzoylformate decarboxylase. This linked a variety of mostly aromatic aldehydes to acetaldehyde to form the corresponding a-hydroxy ketones, both chemo- and stereoselectively [31]. Synthetic thiazolium salts, developed by Stetter and co-workers and similar to thiamine itself [32], have been successfully used by Suzuki et al. for a diastereoselective intramolecular crossed aldehyde-ketone benzoin reaction during the course of an elegant natural product synthesis [33], Stereocontrol was exerted by pre-existing stereocenters in the specific substrates, the catalysts being achiral. 

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