Alkenyl- and Aryl[2-(hydroxymethyl)phenyl]dimethylsilanes:  An Entry to Tetraorganosilicon Reagents for the Silicon-Based Cross-Coupling Reaction

Abstract

Alkenyl- and aryl[2-(hydroxymethyl)phenyl]dimethylsilanes, highly stable tetraorganosilicon reagents, are found to react with aryl and alkenyl iodides in the presence of a palladium catalyst and K2CO3 as a base, significantly milder conditions compared with those ever reported for the silicon-based cross-coupling reactions. The reaction tolerates a wide range of functional groups, including silyl protectors, and allows a gram-scale synthesis to recover and reuse the silicon residue.

Catalytic Amide‐Mediated Methyl Transfer from Silanes to Alkenes in Fujiwara–Moritani Oxidative Coupling

“…The 2-alkoxymethylphenyl group coordinates to silicon, activating an axial aryl group in the ensuing fivecoordinate species. [7] These intimations of Si À Me activation in catalysis were studied under standardized conditions. The simple trimethylsilylmethyl amide 6 [8] and trimethylsilylmethyl ester 7 were employed.…”

Biaryl synthesis using highly stablearyl[2-(hydroxymethyl)phenyl]dimethylsilanes and aryl iodides under fluoride-free conditions

“…Indeed, we have succeeded in recovery of 2 by distillation of a crude product mixture of reaction of alkenyl[2-(hydroxymethyl)-phenyl]dimethylsilanes [8]. However, we did not observe the formation of 2 during the present biaryl synthesis.…”

“…We first examined the reaction of phenylsilane (1a, 0.13 mmol) with 4-iodoanisole (0.10 mmol) in the presence of [(Z 3 -C 3 H 5 )PdCl] 2 (2.5 mol%), tri-2-furylphosphine (15 mol%), CuI (20 mol%), and Cs 2 CO 3 (0.24 mmol) in DMSO at 45 1C for 22 h, reaction conditions slightly modified from those for the successful cross-coupling of alkenylsilanes [8]. Formation of the desired product 4-methoxybiphenyl (3) was estimated to be 79% yield by GC analysis of an aliquot of the reaction mixture (entry 1 of Table 1).…”

“…Independently, we have embarked on design of stable arylsilanes having an activating organofunctional group independent of a transferable aryl group, allowing a diversity of the transformation. We report herein in detail that aryl[2-(hydroxymethyl)phenyl]dimethylsilanes, highly stable tetraorganosilicon compounds, serve as a new entry to arylsilane reagents, which undergo the cross-coupling reaction with various aryl iodides under significantly mild conditions in the presence of palladium/copper catalysts and K 2 CO 3 as a base [8,9].…”

Kreuzkupplungen von Organosiliciumverbindungen in der Naturstoffsynthese

“…[3] Bald darauf wurden stabilere Varianten wie Triallylsilane, [4] Alkoxysilane [5] und [(2-Hydroxymethyl)phenyl]dimethylsilane [6] entwickelt, und unsere Forschungsgruppe führte die Dimethylsilanole ein, die sowohl bei Fluoridaktivierung [7] als auch bei fluoridfreier [8] Reaktionsführung eingesetzt werden können. Darüber hinaus wurden "maskierte" Silanoläquivalente wie Alkoxydimethylsilane, [9] Benzyldimethylsilane, [10] Phenyldimethylsilane, [11] 2-Thienyldimethylsilane [10d, 12] und 2-Pyridyldimethylsilane [13] [18] von Homopropargyloxyhydrosilanen mit anschließender Kreuzkupplung zu den entsprechenden hochsubstituierten E-bzw.…”