89882-20-2

Upstream product

• 42968-14-9 (E)-3-methyl-4-phenyl-3-buten-2-one 
• 57519-88-7 1,1-dichloro-1-phenyl-2,2,2-trimethyldisilane 
• 3839-31-4 dimethyl(phenyl)silyllithium 
• 75583-57-2 lithium bis(dimethyl(phenyl)silyl)cuprate 
• 1896-62-4 (E)-benzalacetone 
• 74-88-4 methyl iodide 
• 89881-82-3 methyl (2RS,3RS)-3-dimethyl(phenyl)silyl-2-methyl-3-phenylpropanoate 
• 1450-18-6 1,1,1-trimethyl-2,2,2-triphenyldisilane 
• 103-26-4 Methyl cinnamate 
• 94286-28-9 4-(dimethylphenylsilyl)-3-phenylpropanoic acid methyl ester 
• 22946-43-6 (E)-methyl-2-methyl-3-phenylacrylate 
• 917-54-4 methyllithium 

Downstream Products

• 56763-59-8 (E)-(3-methylbut-1-ene-1,3-diyl)dibenzene 
• 81640-13-3 (2R*,3S*)-4-phenyl-4-hydroxy-3-methyl-2-butanone 
• 873-66-5 1-propenylbenzene 
• 766-90-5 cis-1-phenyl-1-propylene 

Relevant academic research and scientific papers

THE RELATIVE STEREOCHEMISTRY OF SOME α-METHYL-β-SILYLCARBONYL COMPOUNDS PRODUCED BY THE DIASTEREOSELECTIVE ALKYLATION OF β-SILYLENOLATES

Conjugate addition of lithium bis(dimethylphenylsilyl)cuprate to methyl cinnamate (1), to 4-phenylbut-3-en-2-one (4), and to dec-3-en-2-one (15), followed by methylation of the intermediate enolate, gives largely one diastereoisomer of the α-methyl-β-silylcarbonyl compound (the β-silyl ester (3), 3-methyl-4-dimethyl(phenyl)silyl-4-phenylbutan-2-one (5), and 4-dimethyl(phenyl)silyl-3-methyldecan-3-one (16), respectively).The relative configurations of the two chiral centres in these products are proved to be (RR,SS), (RR,SS), and (RS,SR), respectively, by conversion of the ester 3 into the ketone 5, and by Baeyer-Villiger oxidation of the ketone 5, its diastereoisomer (RS,SR)-3-methyl-4-dimethyl(phenyl)silyl-4-phenylbutan-2-one (8), and the ketone 16 to the corresponding acetates ((RR,SS)-1-phenyl-1-dimethyl(phenyl)silylprop-2-yl acetate (9), (RS,SR)-1-phenyl-1-dimethyl(phenyl)silylprop-2-yl acetate (12), and (RR,SS)-3-dimethyl(phenyl)silylnon-2-yl acetate (17)).Fluoride ion-catalysed elimination of the silyl and acetate groups is not stereospecific when the silyl group is benzylic (9 and 12), but is stereospecifically anti for the saturated acetate (17).Reduction of the acetates 9, 12 and 17 followed by syn-Peterson elimination gives the alkenes E-phenylpropene (11), Z-phenylprop-1-ene (14) and E-non-2-ene (19).

Catalytic asymmetric synthesis of β-hydroxy ketones by palladium-catalyzed asymmetric 1,4-disilylation of α,β-unsaturated ketones

1,4-Disilylation of β,β-unsaturated ketones with 1,1-dichloro-1-phenyl-2,2,2-trimethyldisilane proceeded in the presence of phosphine-palladium catalysts in benzene. High enantio-selectivity (up to 92%) was observed in the disilylation with dichloro[(R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl] palladium(II) as a catalyst (0.5 mol %). The disilylation products, 1-(trimethyisilyloxy)-3-(dichlorophenylsilyl)propenes, were readily converted into optically active α-unsubstituted or anti α-substituted β-(phenyldimethylsilyl) ketones, the oxidation of which gave the corresponding optically active β-hydroxy ketones in high yields.

PALLADIUM-CATALYZED 1,4-DISILYLATION OF α,β UNSATURATED KETONES WITH 1,1-DICHLORO-1-PHENYL-2,2,2-TRIMETHYLDISILANE

1,4-Disilylation of α,β-unsaturated ketones proceeded with 1,1-dichloro-1-phenyl-2,2,2-trimethyldisilane in the presence of a phosphine-palladium catalyst in benzene.Treatment of the disilylation products with an excess of methyllithium generated β-silyl lithium enolates, of which hydrolysis and alkylation gave β-(phenyldimethylsilyl) ketones and anti β-silyl α-alkyl ketones, respectively.

Diastereoselectivity in the Alkylation of Enolates having an Adjacent Silyl Group

The methylation of open-chain enolates having an adjacent silyl group is highly diastereoselective in favour of the isomer (2) having the silyl and methyl groups trans on the carbon chain; protonation of the corresponding enolate, already carrying the methyl group, gives the other diastereoisomer (3), but with somewhat lower diastereoselectivity.