50704-01-3

Upstream product

• 17530-18-6 1-(4-methylpenta-2,3-dien-2-yl)benzene 
• 917-64-6 methyl magnesium iodide 
• 130573-25-0 2-Methylsulfanyl-2-((E)-styryl)-[1,3]dithiane 
• 35739-70-9 dimethyldichlorotitanium(IV) 
• 1896-62-4 (E)-benzalacetone 
• 34713-70-7 2-Phenylpropanal 
• 16666-80-1 triphenylphosphonio-1-methylethanide 
• 101101-05-7 3-hydroxy-2,2-dimethyl-4-phenyl-valeric acid ethyl ester 
• 672-65-1 (1-chloroethyl)benzene 
• 115-11-7 isobutene 
• 13291-18-4 isopropenylmagnesium bromide 
• 140-10-3 (E)-3-phenylacrylic acid 
• 75-24-1 trimethylaluminum 
• 109039-83-0 3-acetoxy-2,2-dimethyl-4-phenyl-valeric acid ethyl ester 

Relevant academic research and scientific papers

Intrazeolite photooxygenation of chiral alkenes. Control of facial selectivity by confinement and cation-π interactions

Depending on the nature of the substituents on the stereogenic carbon atom, the ene reaction of singlet oxygen with several chiral alkenes by confinement within thionin-supported zeolite NaY, may exhibit significant changes on facial selectivity by comparison to their photooxygenation reaction in solution. It is proposed that, apart from the conformational consequences as a result of the alkene confinement within the zeolite cavities, a synergism between Na+-π interactions and singlet oxygen-Na+ interactions plays a significant role in the transition states of ene hydroperoxidation. Within NaY, the diastereoselectivity may significantly depend on the site selectivity, as probed through specific deuterium labelling of trisubstituted alkenes bearing a gem-dimethyl group. In certain cases, a remote stereogenic centre relative to the reacting double bond may induce enhanced diastereoselection and regioselectivity.

Remarkable Change of the Diastereoselection in the Dye-Sensitized Ene Hydroperoxidation of Chiral Alkenes by Zeolite Confinement

(Equation presented) The ene reaction of singlet oxygen with chiral trisubstituted alkenes bearing an alkyl and a phenyl group at the stereogenic center is erythro diastereoselective in solution and threo diastereoselective if carried out within zeolite Na-Y. The change of the diastereoselection trend by zeolite confinement is attributed to a synergism of steric effects and cation-π interactions.

Allylic dithioacetal as a propene-1,3-Zwitterion synthon. Regioselective conversion of C-S bonds in allylic dithioacetals into C-C bonds

Reaction of allylic dithioacetals with organocuprate or organolithium reagent followed by treatment with a variety of alkyl electrophiles gives the corresponding E and Z isomeric mixture of vinyl sulfides in good yield. Further cross coupling with a Grignard reagent in the presence of NiCl2(dppe) affords the corresponding alkylation products in good yield. In general, the Grignard reagent having the same alkyl group as the R2 substituent in 1 is employed so that the stereochemical problem in coupling products can be lifted.

NiCl2(dppe)-Catalyzed Geminal Dialkylation of Dithioacetals and Trimethylation of Ortho Thioesters

NiCl2(dppe)-catalyzed cross-coupling of cinnamaldehyde dithioacetals gave the corresponding geminal dimethylation products in excellent yields.Allylic ortho thioesters afforded regioselectively the corresponding trimethylation products.The reaction may occur via an 18-electron ?-allyl intermediate, which undergoes facile reductive elimination to afford the geminal dimethylation product.Benzylic dithioacetals having an ortho amino group gave 2-isopropylanilines exclusively.The reaction of benzylic dithioacetals with EtMgBr under the same conditions yielded geminal diethylation products.

Syn-Diastereoselective Alkenylation with a Modified Seyferth-Wittig Reagent: Modification of the Silyl Substituents and Isopropenylation

The introduction of electronegative substituents onto the silyl group of triaryl(2-silylethylidene)phosphorane promotes eliminative silyl migration relative to the Wittig reaction; the combination of this effect with modification of the phosphorane substituents leads to highly diastereoselective reagents for alkenylation.

Direct Geminal Dimethylation of Ketones and Exhaustive Methylation of Carboxylic Acid Chlorides Using Dichlorodimethyltitanium

The reaction of ketones with an excess of (CH3)2TiCl2 (6) leads to the replacement of the carbonyl oxygen atom by two methyl groups.This mild method of direct geminal dimethylation involves Grignard-type addition followed by formation of tertiary carbocations which are captured by methyltitanium species.Additional functional groups such as primary alkyl chlorides, thioethers, aromatics, ethers and esters are tolerated, but not thioketals.The procedure has been applied to the synthesis of (+/-)-cuparene (44).Similarly, carboxylic acid chlorides are converted to tert-butyl derivatives.