Aldehydes cross-coupling reaction

Few examples of what might be described as an intermolecular coupling reaction on inactivated alkenes has appeared [62], Thus ketyl radicals generated from aromatic aldehydes and ketones underwent intermolecular addition to the para position of another aldehyde. Cross-coupling reactions are not feasible in these systems and typically yields are quite low. 

The hydrosi(ly)lations of alkenes and alkynes are very important catalytic processes for the synthesis of alkyl- and alkenyl-silanes, respectively, which can be further transformed into aldehydes, ketones or alcohols by estabhshed stoichiometric organic transformations, or used as nucleophiles in cross-coupling reactions. Hydrosilylation is also used for the derivatisation of Si containing polymers. The drawbacks of the most widespread hydrosilylation catalysts [the Speier s system, H PtCl/PrOH, and Karstedt s complex [Pt2(divinyl-disiloxane)3] include the formation of side-products, in addition to the desired anh-Markovnikov Si-H addition product. In the hydrosilylation of alkynes, formation of di-silanes (by competing further reaction of the product alkenyl-silane) and of geometrical isomers (a-isomer from the Markovnikov addition and Z-p and -P from the anh-Markovnikov addition. Scheme 2.6) are also possible. 

A cross-coupling reaction of aldehydes with a-diketones proceeded in the presence of water to give the corresponding adducts in moderate to good yield. It is possible to use the substrates such as phenyl-glyoxal monohydrate, aqueous methylglyoxal, formalin, and aqueous a-chloroacetaldehyde for this reaction.330... 

Chamoin S, Houldsworth S, Kruse CG, Bakker WI, Snieckus V. The Suzuki-Miyaura cross coupling reactions on solid support. Link to solution phase directed ortho metalation. The Leznoff acetal linker approach to biaryl and heterobiaryl aldehydes. Tetrahedron Lett 1998 39 4179-4182. 

In recentyears, metal NPs synthesized in ILs were recognized as suitable materials to promote the formation of chemical bonds in reactions other than palladium-catalyzed carbon-carbon cross-coupling reactions. For example, aldehydes and esters... 

The palladium-catalyzed cross-coupling reaction featured in this procedure occurs under neutral conditions in the presence of many synthetically useful functional groups (e.g. alcohol, ester, nitro, acetal, ketone, and aldehyde). The reaction works best in N,N-dimethylformamide with bis(triphenylphosphine)palladium(ll) chloride, PdCI2(PPh3)2, as the catalyst. Lithium chloride is added to prevent decomposition of the catalyst.143 13 It is presumed that conversion of the intermediate aryl palladium triflate to an aryl palladium chloride is required for the transmetallation step to proceed.9... 

Cross-coupling reactions of nitrones with aldehydes and ketones make it possible to synthesize vicinal amino alcohols, which are common in natural products. These transformations have been performed by a new method of reduction... 

The cross-coupling reaction of homoallylic alcohols with aldehydes in the presence of bismuth trichloride in solvent-free conditions under microwave irradiation generated 4-chloro-2,6-disubstituted tetrahydropyrans with high c/.v-diastereos-electivity [15]. The reaction of benzaldehyde with l-phenyl-3-buten-l-ol in the presence of bismuth trichloride under microwave irradiation gave the corresponding... 

Cross-coupling reactions (Sonogashira or Heck reactions) of 1-bromo-l-fluor-oalkenes, which are generally prepared through the reaction of an aldehyde with CFBra and PPha. ... 

In 1991, Inanaga achieved Sml2-mediated intermolecular cross-coupling between C=0 (ketones or aldehydes) and C=N by using 0-benzyl formaldoxime as a C=N component7 The reaction requires HMPA as a co-solvent and a suitable proton source such as /-butyl alcohol or ethylene glycol. A cross-coupling reaction between ketones and... 

P. Dtinkelmann, D. Kolter-Jung, A. Nitsche, A. S. Demir, P. Siegert, B. Lingen, M. Baumann, M. Pohl, M. Muller, Development of a donor-acceptor concept for enzymatic cross-coupling reactions of aldehydes, the first asymmetric cross-benzoin condensation. f Am. Chem. Soc. 2002, 124, 12084-12085. 

When the first electrophile was not a ketone or an aldehyde, as illustrated for the reaction of 276 with crotonyl chloride, the intermediate chelated alkenylmetal 278 could also be subjected to iodinolysis or palladium-catalyzed cross-coupling reactions with aryl and alkenyl iodides in the presence of a stoichiometric amount of CuBr as a promotor as well as a polar cosolvent such as IV, IV-di methyl acetamide (DMA) (equation 131)165 166. 

Chamoin, S. Houldsworth, S. Kruse, C. G. Bakker, W. I. Snieckus, V. The Suzuki-Miyaura Cross Coupling Reactions on Solid Support. Link to Solution Phase Directed ortho Metalation. The Leznoff Acetal Linker Approach to Biaryl and Heterobiaryl Aldehydes, Tetrahedron Lett. 1998, 39, 4179-4182. 

Carreira and co-workers have also extended the scope of aldehydes that may be utilized in catalytic addition reactions to include stannylpropenal 108 as a substrate (Table 8B2.12, Entry 7). The adduct produced from the aldol addition of 105 is isolated with 92% ee and serves as a useful building block, as it is amenable for further synthetic elaboration (Scheme 8B2.9). Thus, vinylstannane 109 is a substrate for Stille cross-coupling reactions to give a diverse family of protected acetoacetate adducts 110. Following deprotection of the masked keto ester, the corresponding hydroxy keto ester 111 may be converted to either the syn or anti skipped polyols 112 or 113. A recent total synthesis of macrolactin A by Carreira and co-workers utilizes aldol... 

The one-pot Stille cross-coupling reaction of compound 256 produced all four isomeric thieno[3,2-c]naphthyridines (1994JHC11). The stepwise formation of the C(7)-C(7a) and C(4)-N(5) bonds of the thieno[3,2-c]pyridine system can be considered as a modification of the above-described approaches. For example, aldehyde 256 reacts with arene 265 to give 266 reduction of its nitro group is accompanied by cyclization to form thieno[3,2-c]isoquinoline A-oxide (267) (1990JHC1127). 

Activated olefins can also be subjected to cathodic C—C cross coupling reactions with carbonyl compounds. An example of this is the synthesis of y-hydroxynitriles from acrylonitrile and aliphatic aldehydes 353 > ... 

The time consuming chromatographical purification of heterocycles 28 and 29 slowed down the rate of library production. A phase separation using fluorous chemistry was employed by Zhang and Lu to address the workup and purification of fused 3-aminoimidazo[ l,2-a]pyridines (such as 30) [54]. Thus, attachment of a perfluorooctanesulfonyl tag to aldehydes and subsequent Ugi three-component microwave-assisted condensations with 2-aminopyridines and isocyanides furnished the desired heterocycles 30, which were conveniently isolated by fluorous solid-phase extraction. The fluorous tag could be subsequently used as an activating group in the post-condensation modifications, such as Suzuki-Miyaura cross-coupling reactions. 

Lithiation of compound 560 with s-BuLi-TMEDA in THF at —78 °C following an inverse addition protocol provided the anion 561. It reacts with primary alkyl iodides and triflates, silyl chlorides, diphenyl disulfide, epoxides, aldehydes, ketones, imines, acyl chlorides, isocyanates and sulfonyl fluorides to yield the expected compounds 562 (Scheme 152). The transmetallation of compound 561 with ZnBr2 allowed the palladium-catalyzed cross-coupling reaction with aryl and vinyl bromides837. When the reaction was quenched with 1,2-dibromotetrafluoroethane, the corresponding bromide 562 (X = Br) is obtained838. 

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