Asymmetric Hydrosilylation of 1-Alkenes Catalyzed by Palladium–MOP

Abstract

Asymmetric hydrosilylation of simple terminal alkenes (RCH=CH2) with trichlorosilane at 40 °C in the presence of 1 × 10−3 or 1 × 10−4 molar amounts of palladium catalyst prepared in situ from [PdCl(η3-C3H5)]2 and (S)-2-diphenylphosphino-2′-methoxy-1,1′-binaphthyl ((S)-MeO-MOP) proceeded with unusual regioselectivity and with high enantioselectivity to give high yields of 2-(trichlorosilyl)alkanes together with a minor amount of 1-(trichlorosilyl)alkanes. Optically active alcohols, RCH(OH)CH3, were obtained by oxidation of the carbon–silicon bond. Regioselectivities for forming 2-silylalkanes over 1-silylalkanes and enantiomeric purities of alcohols are as follows: R = n-C4H9: 89/11, 94% ee (R). R = n-C6H13: 93/7 95% ee (R). R = n-C10H21: 94/6, 95% ee (R). R = PhCH2CH2: 81/19, 97% ee (S). R = PhCH2CH2CH2: 80/20, 92% ee (R). R = cyclo-C6H11: 66/34, 96% ee (R). A similar hydrosilylation of 1-alkenes, 4-pentenyl benzoate and 1,5-heptadiene gave corresponding 2-alkanols of 90% ee and 87% ee, respectively, the ester carbonyl and the internal double bond remaining intact.

Polyimide-Supported Dichloro-1,3-bis(p-dimethylaminobenzyl)benzimidazolidin-2-ilidenruthenium (II) as Effective Catalyst for Hydrosilylation Reactions

“…Moreover, it is applied to the reduction of ketones to secondary alcohols [27]. In general, the term hydrosilylation is used to describe an addition reaction of hydrosilanes to double and triple bonds and in the laboratory, hydrosi- lylation is a very convenient method for the synthesis of arrange of organosilicon compounds.…”

Syntheses and characterizations of methylpalladium complexes bearing a biphenyl-based bulky phosphine ligand: Weak interactions suggested by NBO and QTAIM analyses

“…1) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. On the other hand, Hayashi reported binaphthyl-based monodentate phosphine ligands (MOP (6) [18][19][20][21][22][23] to achieve highly efficient asymmetric hydrosilylation and allylic substitution reactions. Vyskočyl, Kočovskŷ, Ding, and Mikami also reported a derivatization of MOP to MAP (7) and its application to the asymmetric allylic substitution [25,26].…”

Asymmetric Hydrosilylation

“…Asymmetric hydrosilylation of 4-pentenyl benzoate and 1,5-heptadiene gave the corresponding 2-alkanols of 90% ee and 87% ee, respectively. The ester carbonyl and the internal double bond remained intact [25]. The high selectivity was also observed with MOP ligands 10b, 10c, and 10d, which have other substituents than methoxy at the 2′ position [25] (Scheme 3-6).…”

“…The ester carbonyl and the internal double bond remained intact [25]. The high selectivity was also observed with MOP ligands 10b, 10c, and 10d, which have other substituents than methoxy at the 2′ position [25] (Scheme 3-6). Thus, the hydrosilylation of 1-octene (11b) with MOP ligands substituted with benzyloxy or isopropoxy gave over 91% enantioselectivity and over 80% branch selectivity, suggesting that the steric bulkiness of the 2′-substituents has little influence on this asymmetric hydrosilylation.…”

“…However, palladium-catalyzed hydrosilylation has been neglected because it is difficult to avoid reduction of palladium complex to inactive metal in this process. Recently a palladium complex coordinated with an axially chiral monodentate phosphine ligand, MeO-MOP (10a) or its analogs [23], has been demonstrated to exhibit extremely high activity for the asymmetric hydrosilylation of alkyl-substituted terminal olefins along with an unprecedented regioselectivity (Scheme 3-5) [24,25]. Simple terminal olefins 11 were transformed efficiently into the corresponding optically active 2-alkanols 14 with enantio-selectivities ranging between 94% and 97% ee by the catalytic hydrosilylation-oxidation procedure.…”