Designing Cross‐Coupling Reactions using Aryl(trialkyl)silanes

Abstract

Organo(trialkyl)silanes have several advantages, including high stability, low toxicity, good solubility, easy handling, and ready availability compared with heteroatom-substituted silanes. However, methods for the cross-coupling of organo(trialkyl)silanes are limited, most probably because of their exceeding robustness. Thus, a practical method for the cross-coupling of organo(trialkyl)silanes has been a long-standing challenging research target. This article discusses how aryl(trialkyl)silanes can be used in cross-coupling reactions. A pioneering example is Cu catalytic conditions with the use of electron-accepting aryl- or heteroaryl(triethyl)silanes and aryl iodides. The reaction forms biaryls or teraryls. This design concept can be extended to Pd/Cu -catalyzed cross-coupling polymerization reactions between such silanes and aryl bromides or chlorides and to Cu -catalyzed alkylation using alkyl halides.

Nickel-Mediated Enantiospecific Silylation via Benzylic C–OMe Bond Cleavage

“…Despite the success of Grignard reagents (unhindered) as a coupling partner in C­(sp 3 )–OMe bond cleavage, the cross-coupling reactions of ethers remain essentially limited to C–C bond-forming reactions. On the contrary, organosilicons (C–Si bond) have widespread applications across various disciplines − and are versatile intermediates in organic synthesis. − Consequently, considerable effort in cross-coupling reactions has been spent to contribute to the synthesis of organosilanes, including silylation via C–N bond cleavage (Scheme b). − Recently, for the first time, we introduced an economical Me 3 SiMgI (directly synthesized from TMSI) in cross-coupling reactions [C­(sp 2 )–OCb bond cleavage] for the synthesis of ArSiMe 3 , a useful organosilane for further synthetic transformations (Scheme b).…”

Cross-Coupling of Heteroatomic Electrophiles

“…Kitamura took advantage of a similar domino reaction of alkyne-tethered pentafluorobenzoyloximes (130) in the creation of substituted isoindoles (131). 262 In this domino reaction, the vinylpalladium species undergoes transmetalation with an arylboronic acid followed by reductive elimination of the arylated product (131, Figure 35).…”

“…For example, organic compounds bearing compounds bearing silicon , have increasingly been used not only as coupling partners in allylation, Hiyama, and related cross-couplings − but also as masked alcohols or carbonyls through the Fleming–Tamao oxidation. , Organosilicon compounds have also found extensive use in industrial and aerospace applications as lubricants or cryogenic fluids . Silicon atoms are also found in the structures of a number of small-molecule agrochemicals including the silylmethyltriazole fungicide Flusilazole (DPX-H6573) ( 4 , Figure ).…”

Transition-Metal-Free Silylation of Unactivated C(sp2)–H Bonds with tert-Butyl-Substituted Silyldiazenes

“…Aromatic organosilanes have become invaluable chemical tools in drug discovery and material science or as intermediates in synthetic chemistry . Most arylsilanes have traditionally been synthesized from the corresponding arylhalides (bromide or iodide) .…”